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Acronyms in .NET
ADO - ActiveX Data Object - Microsoft ActiveX Data Objects (ADO) is a collection of Component Object Model objects for accessing different types of data sources.
AJAX - Asynchronouse Javascript and XML - Ajax is a web development technology used for creating interactive web pages with fast data rendering by enabling partial postbacks on a web page (That means a section of the web page is rendered again, instead of the complete web page. This is achieved using Javascript, XML, JSON (Javascript Notation Language) and the XMLHttpRequest object in javascript.
ASP - Active Server Pages - Microsoft's Server side script engine for creating dynamic web page.
C# - C Sharp - Microsoft Visual C# is an object oriented programming language based on the .NET Framework. It includes features of powerful languages like C++, Java, Delphi and Visual Basic.
CAO - Client Activated Object - Objects created on the server upon the client's request. This is used in Remoting.
CCW - COM Callable Wrapper - This component is used when a .NET component needs to be used in COM.
CIL - Common Intermediate Language - Its actually a low level human readable language implementation of CLI. All .NET-aware languages compile the source oode to an intermediate language called Common Intermediate Language using the language specific compiler.
CLI - Common Language Infrastructure - This is a subset of CLR and base class libraries that Microsoft has submitted to ECMA so that a third-party vendor can build a .NET runtime on another platform.
CLR - Common Language Runtime - It is the main runtime machine of the Microsoft .NET Framework. It includes the implementation of CLI. The CLR runs code in the form of bytes, called as bytecode and this is termed MSIL in .NET.
CLS - Common Language Specification - A type that is CLS compliant, may be used across any .NET language. CLS is a set of language rules that defines language standards for a .NET language and types declared in it. While declaring a new type, if we make use of the [CLSCompliant] attribute, the type is forced to conform to the rules of CLS.
COFF - Common Object File Format - It is a specification format for executables.
COM - Component Object Model - reusable software components. The tribe of COM components includes COM+, Distributed COM (DCOM) and ActiveX® Controls.
CSC.exe - C Sharp Compiler utility
CTS - Common Type System - It is at the core of .NET Framework's cross-language integration, type safety, and high-performance code execution. It defines a common set of types that can be used with many different language syntaxes. Each language (C#, VB.NET, Managed C++, and so on) is free to define any syntax it wishes, but if that language is built on the CLR, it will use at least some of the types defined by the CTS.
DBMS - Database Management System - a software application used for management of databases.
DISCO - Discovery of Web Services. A Web Service has one or more. DISCO files that contain information on how to access its WSDL.
DLL - Dynamic Link Library - a shared reusable library, that exposes an interface of usable methods within it.
DOM - Document Object Model - is a language independent technology that permits scripts to dynamically updated contents of a document (a web page is also a document).
ECMA - European Computer Manufacturer's Association - Is an internation organisation for computer standards.
GC - Garbage Collector - an automatic memory management system through which objects that are not referenced are cleared up from the memory.
GDI - Graphical Device Interface - is a component in Windows based systems, that performs the activity of representing graphical objects and outputting them to output devices.
GAC - Global Assembly Cache - Is a central repository of reusable libraries in the .NET environment.
GUI - Graphic User Interface - a type of computer interface through which user's may interact with the Computer using different types of input & output devices with a graphical interface.
GUID - Globally Unique Identifier - is a unique reference number used in applications to refer an object.
HTTP - Hyper Text Transfer Protocol - is a communication protocol used to transfer information in the internet. HTTP is a request-response protocol between servers and clients.
IDE - Integrated Development Environment - is a development environment with source code editor with a compiler(or interpretor), debugging tools, designer, solution explorer, property window, object explorer etc.
IDL - Interface Definition Language - is a language for defining software components interface.
ILDASM - Intermediate Language Disassembler - The contents of an assembly may be viewed using the ILDASM utility, that comes with the .NET SDK or the Visual Studio.NET. The ildasm.exe tool may also be used in the command line compiler.
IIS - Internet Information Server - Is a server that provides services to websites and even hosts websites.
IL - Intermediate Language - is the compiled form of the .NET language source code. When .NET source code is compiled by the language specific compiler (say we compile C# code using csc.exe), it is compiled to a .NET binary, which is platform independent, and is called Intermediate Language code. The .NET binary also comprises of metadata.
JIT - Just in Time (Jitter) - is a technology for boosting the runtime performance of a system. It converts during runtime, code from one format into another, just like IL into native machine code. Note that JIT compilation is processor specific. Say a processor is X86 based, then the JIT compilation will be for this type of processor.
MBR - MarshallByReference - The caller recieves a proxy to the remote object.
MBV - MarshallByValue - The caller recieves a copy of the object in its own application domain.
MDI - Multiple Document Interface - A window that resides under a single parent window.
MSIL - Microsoft Intermediate Language - now called CIL.
Orcas - Codename for Visual Studio 2008
PE - Portable Executable - an exe format file that is portable.
RAD - Rapid Application Development
RCW - Runtime Callable Wrapper - This component is used when a .NET needs to use a COM component.
SAX - Simple API for XML - It is a serial access parser API for XML. The parser is event driven and the event gets triggered when an XML feature is encountered.
SDK - Software Development Kit
SMTP - Simple Mail Transfer Protocol - a text based protocol for sending mails.
SN.exe - Strong Name Utility - a tool to make strong named assemblies.
SQL - Structured Query Language - a language for management of data in a relational structure.
SOAP - Simple Object Access Protocol - a protocol used for exchange of xml based messages across networks.
TCP - Transmission Control Protocol - data exchange protocol across networks using streamed sockets.
UI - User Interface
URI - Uniform Resource Identifier
URL - Uniform Resource Locator
UDDI - Universal Description, Discovery and Integration - it is a platform independent business registration across the internet.
WAP - Wireless Access Protocol - a protocol that enables access to the internet from mobile phones and PDAs.
WC - Windows Cardspace - Part of .NET 3.0 framework, that enables users to secure and store digital identities of a person, and a provision to a unified interface for choosing the identity for a particular transaction, like logging in to a website.
WCF - Windows Communication Foundation - Part of .NET 3.0 framework, that enables communication between applications across machines.
WF - Windows Workflow Foundation - Part of .NET 3.0 framework, used for defining, execution and management of reusable workflows.
WKO - Well Known Object - These are MBR types whose lifetime is controlled by the server's application domain.
WPF - Windows Presentation Foundation - Part of .NET 3.0 framework, is the graphical subsystem of the .NET 3.0 framework.
WSDL - Web Services Description Language - is an XML based language for describing web services.
WML - Wireless Markup Language - is a content format for those devices that use Wireless Application Protocol.
VB.NET - Visual Basic .NET - .NET based language. Its the .NET implementation of VB6, the most widely used language in the world.
VBC.exe - VB.NET Compiler
VES - Virtual Execution System - It provides the environment for execution of managed code. It provides direct support for a set of built in data types, defines a hypothetical machine with an associated machine model and state, a set of control flow constructs, and an exception handling model. To a large extent, the purpose of the VES is to provide the support required to execute the Common Intermediate Language instruction set.
VS - Visual Studio
VSS - Visual Source Safe - An IDE by Microsoft, to maintain source code versions and security.
VSTS - Visual Studio Team Suite - Visual Studio Team System - it is an extended version of Visual Studio .NET. It has a set of collaboration and development tools for software development process.
XML - Extensible Markup Language - is a general purpose well formed markup language.
Wednesday, July 16, 2008
Short Answer .NET Interview Questions (PAGE 5)
Q81. What technique is used to figure out that the page request is a postback?
Ans. The IsPostBack property of the page object may be used to check whether the page request is a postback or not. IsPostBack property is of the type Boolean.
Q82. Which event of the ASP.NET page life cycle completely loads all the controls on the web page?
Ans. The Page_load event of the ASP.NET page life cycle assures that all controls are completely loaded. Even though the controls are also accessible in Page_Init event but here, the viewstate is incomplete.
Q83. How is ViewState information persisted across postbacks in an ASP.NET webpage?
Ans. Using HTML Hidden Fields, ASP.NET creates a hidden field with an ID="__VIEWSTATE" and the value of the page's viewstate is encoded (hashed) for security.
Q84. What is the ValidationSummary control in ASP.NET used for?
Ans. The ValidationSummary control in ASP.NET displays summary of all the current validation errors.
Q85. What is AutoPostBack feature in ASP.NET?
Ans. In case it is required for a server side control to postback when any of its event is triggered, then the AutoPostBack property of this control is set to true.
Q86. What is the difference between Web.config and Machine.Config in .NET?
Ans. Web.config file is used to make the settings to a web application, whereas Machine.config file is used to make settings to all ASP.NET applications on a server(the server machine).
Q87. What is the difference between a session object and an application object?
Ans. A session object can persist information between HTTP requests for a particular user, whereas an application object can be used globally for all the users.
Q88. Which control has a faster performance, Repeater or Datalist?
Ans. Repeater.
Q89. Which control has a faster performance, Datagrid or Datalist?
Ans. Datalist.
Q90. How to we add customized columns in a Gridview in ASP.NET?
Ans. Make use of the TemplateField column.
Q91. Is it possible to stop the clientside validation of an entire page?
Ans. Set Page.Validate = false;
Q92. Is it possible to disable client side script in validators?
Ans. Yes. simply EnableClientScript = false.
Q93. How do we enable tracing in .NET applications?
Ans. <%@ Page Trace="true" %>
Q94. How to kill a user session in ASP.NET?
Ans. Use the Session.abandon() method.
Q95. Is it possible to perform forms authentication with cookies disabled on a browser?
Ans. No, it is not possible.
Q96. What are the steps to use a checkbox in a gridview?
Ans.
Q97. What are design patterns in .NET?
Ans. A Design pattern is a repeatitive solution to a repeatitive problem in the design of a software architecture.
Q98. What is difference between dataset and datareader in ADO.NET?
Ans. A DataReader provides a forward-only and read-only access to data, while the DataSet object can carry more than one table and at the same time hold the relationships between the tables. Also note that a DataReader is used in a connected architecture whereas a Dataset is used in a disconnected architecture.
Q99. Can connection strings be stored in web.config?
Ans. Yes, in fact this is the best place to store the connection string information.
Q100. Whats the difference between web.config and app.config?
Ans. Web.config is used for web based asp.net applications whereas app.config is used for windows based applications.
Ans. The IsPostBack property of the page object may be used to check whether the page request is a postback or not. IsPostBack property is of the type Boolean.
Q82. Which event of the ASP.NET page life cycle completely loads all the controls on the web page?
Ans. The Page_load event of the ASP.NET page life cycle assures that all controls are completely loaded. Even though the controls are also accessible in Page_Init event but here, the viewstate is incomplete.
Q83. How is ViewState information persisted across postbacks in an ASP.NET webpage?
Ans. Using HTML Hidden Fields, ASP.NET creates a hidden field with an ID="__VIEWSTATE" and the value of the page's viewstate is encoded (hashed) for security.
Q84. What is the ValidationSummary control in ASP.NET used for?
Ans. The ValidationSummary control in ASP.NET displays summary of all the current validation errors.
Q85. What is AutoPostBack feature in ASP.NET?
Ans. In case it is required for a server side control to postback when any of its event is triggered, then the AutoPostBack property of this control is set to true.
Q86. What is the difference between Web.config and Machine.Config in .NET?
Ans. Web.config file is used to make the settings to a web application, whereas Machine.config file is used to make settings to all ASP.NET applications on a server(the server machine).
Q87. What is the difference between a session object and an application object?
Ans. A session object can persist information between HTTP requests for a particular user, whereas an application object can be used globally for all the users.
Q88. Which control has a faster performance, Repeater or Datalist?
Ans. Repeater.
Q89. Which control has a faster performance, Datagrid or Datalist?
Ans. Datalist.
Q90. How to we add customized columns in a Gridview in ASP.NET?
Ans. Make use of the TemplateField column.
Q91. Is it possible to stop the clientside validation of an entire page?
Ans. Set Page.Validate = false;
Q92. Is it possible to disable client side script in validators?
Ans. Yes. simply EnableClientScript = false.
Q93. How do we enable tracing in .NET applications?
Ans. <%@ Page Trace="true" %>
Q94. How to kill a user session in ASP.NET?
Ans. Use the Session.abandon() method.
Q95. Is it possible to perform forms authentication with cookies disabled on a browser?
Ans. No, it is not possible.
Q96. What are the steps to use a checkbox in a gridview?
Ans.
Q97. What are design patterns in .NET?
Ans. A Design pattern is a repeatitive solution to a repeatitive problem in the design of a software architecture.
Q98. What is difference between dataset and datareader in ADO.NET?
Ans. A DataReader provides a forward-only and read-only access to data, while the DataSet object can carry more than one table and at the same time hold the relationships between the tables. Also note that a DataReader is used in a connected architecture whereas a Dataset is used in a disconnected architecture.
Q99. Can connection strings be stored in web.config?
Ans. Yes, in fact this is the best place to store the connection string information.
Q100. Whats the difference between web.config and app.config?
Ans. Web.config is used for web based asp.net applications whereas app.config is used for windows based applications.
Short Answer .NET Interview Questions (PAGE 4)
Q61. Is a delegate a type-safe functions pointer?
Ans. Yes
Q62. What is the return type of an event in .NET?
Ans. There is No return type of an event in .NET.
Q63. Is it possible to specify an access specifier to an event in .NET?
Ans. Yes, though they are public by default.
Q64. Is it possible to create a shared event in .NET?
Ans. Yes, but shared events may only be raised by shared methods.
Q65. How to prevent overriding of a class in .NET?
Ans. Use the keyword NotOverridable in VB.NET and sealed in C#.
Q66. How to prevent inheritance of a class in .NET?
Ans. Use the keyword NotInheritable in VB.NET and sealed in C#.
Q67. What is the purpose of the MustInherit keyword in VB.NET?
Ans. MustInherit keyword in VB.NET is used to create an abstract class.
Q68. What is the access modifier of a member function of in an Interface created in .NET?
Ans. It is always public, we cant use any other modifier other than the public modifier for the member functions of an Interface.
Q69. What does the virtual keyword in C# mean?
Ans. The virtual keyword signifies that the method and property may be overridden.
Q70. How to create a new unique ID for a control?
Ans. ControlName.ID = "ControlName" + Guid.NewGuid().ToString(); //Make use of the Guid class
Q71A. What is a HashTable in .NET?
Ans. A Hashtable is an object that implements the IDictionary interface, and can be used to store key value pairs. The key may be used as the index to access the values for that index.
Q71B. What is an ArrayList in .NET?
Ans. Arraylist object is used to store a list of values in the form of a list, such that the size of the arraylist can be increased and decreased dynamically, and moreover, it may hold items of different types. Items in an arraylist may be accessed using an index.
Q72. What is the value of the first item in an Enum? 0 or 1?
Ans. 0
Q73. Can we achieve operator overloading in VB.NET?
Ans. Yes, it is supported in the .NET 2.0 version, the "operator" keyword is used.
Q74. What is the use of Finalize method in .NET?
Ans. .NET Garbage collector performs all the clean up activity of the managed objects, and so the finalize method is usually used to free up the unmanaged objects like File objects, Windows API objects, Database connection objects, COM objects etc.
Q75. How do you save all the data in a dataset in .NET?
Ans. Use the AcceptChanges method which commits all the changes made to the dataset since last time Acceptchanges was performed.
Q76. Is there a way to suppress the finalize process inside the garbage collector forcibly in .NET?
Ans. Use the GC.SuppressFinalize() method.
Q77. What is the use of the dispose() method in .NET?
Ans. The Dispose method in .NET belongs to IDisposable interface and it is best used to release unmanaged objects like File objects, Windows API objects, Database connection objects, COM objects etc from the memory. Its performance is better than the finalize() method.
Q78. Is it possible to have have different access modifiers on the get and set methods of a property in .NET?
Ans. No we can not have different modifiers of a common property, which means that if the access modifier of a property's get method is protected, and it must be protected for the set method as well.
Q79. In .NET, is it possible for two catch blocks to be executed in one go?
Ans. This is NOT possible because once the correct catch block is executed then the code flow goes to the finally block.
Q80. Is there any difference between System.String and System.StringBuilder classes?
Ans. System.String is immutable by nature whereas System.StringBuilder can have a mutable string in which plenty of processes may be performed.
Ans. Yes
Q62. What is the return type of an event in .NET?
Ans. There is No return type of an event in .NET.
Q63. Is it possible to specify an access specifier to an event in .NET?
Ans. Yes, though they are public by default.
Q64. Is it possible to create a shared event in .NET?
Ans. Yes, but shared events may only be raised by shared methods.
Q65. How to prevent overriding of a class in .NET?
Ans. Use the keyword NotOverridable in VB.NET and sealed in C#.
Q66. How to prevent inheritance of a class in .NET?
Ans. Use the keyword NotInheritable in VB.NET and sealed in C#.
Q67. What is the purpose of the MustInherit keyword in VB.NET?
Ans. MustInherit keyword in VB.NET is used to create an abstract class.
Q68. What is the access modifier of a member function of in an Interface created in .NET?
Ans. It is always public, we cant use any other modifier other than the public modifier for the member functions of an Interface.
Q69. What does the virtual keyword in C# mean?
Ans. The virtual keyword signifies that the method and property may be overridden.
Q70. How to create a new unique ID for a control?
Ans. ControlName.ID = "ControlName" + Guid.NewGuid().ToString(); //Make use of the Guid class
Q71A. What is a HashTable in .NET?
Ans. A Hashtable is an object that implements the IDictionary interface, and can be used to store key value pairs. The key may be used as the index to access the values for that index.
Q71B. What is an ArrayList in .NET?
Ans. Arraylist object is used to store a list of values in the form of a list, such that the size of the arraylist can be increased and decreased dynamically, and moreover, it may hold items of different types. Items in an arraylist may be accessed using an index.
Q72. What is the value of the first item in an Enum? 0 or 1?
Ans. 0
Q73. Can we achieve operator overloading in VB.NET?
Ans. Yes, it is supported in the .NET 2.0 version, the "operator" keyword is used.
Q74. What is the use of Finalize method in .NET?
Ans. .NET Garbage collector performs all the clean up activity of the managed objects, and so the finalize method is usually used to free up the unmanaged objects like File objects, Windows API objects, Database connection objects, COM objects etc.
Q75. How do you save all the data in a dataset in .NET?
Ans. Use the AcceptChanges method which commits all the changes made to the dataset since last time Acceptchanges was performed.
Q76. Is there a way to suppress the finalize process inside the garbage collector forcibly in .NET?
Ans. Use the GC.SuppressFinalize() method.
Q77. What is the use of the dispose() method in .NET?
Ans. The Dispose method in .NET belongs to IDisposable interface and it is best used to release unmanaged objects like File objects, Windows API objects, Database connection objects, COM objects etc from the memory. Its performance is better than the finalize() method.
Q78. Is it possible to have have different access modifiers on the get and set methods of a property in .NET?
Ans. No we can not have different modifiers of a common property, which means that if the access modifier of a property's get method is protected, and it must be protected for the set method as well.
Q79. In .NET, is it possible for two catch blocks to be executed in one go?
Ans. This is NOT possible because once the correct catch block is executed then the code flow goes to the finally block.
Q80. Is there any difference between System.String and System.StringBuilder classes?
Ans. System.String is immutable by nature whereas System.StringBuilder can have a mutable string in which plenty of processes may be performed.
Short Answer .NET Interview Questions (PAGE 3)
Q41. How to instruct the garbage collector to collect unreferenced data?
Ans. We may call the garbage collector to collect unreferenced data by executing the System.GC.Collect() method.
Q42. How can we set the Focus on a control in ASP.NET?
Ans. txtBox123.Focus(); OR Page.SetFocus(NameOfControl);
Q43. What are Partial Classes in Asp.Net 2.0?
Ans. In .NET 2.0, a class definition may be split into multiple physical files but partial classes do not make any difference to the compiler as during compile time, the compiler groups all the partial classes and treats them as a single class.
Q44. How to set the default button on a Web Form?
Ans.
Q45.Can we force the garbage collector to run?
Ans. Yes, using the System.GC.Collect(), the garbage collector is forced to run in case required to do so.
Q46. What is Boxing and Unboxing?
Ans. Boxing is the process where any value type can be implicitly converted to a reference type object while Unboxing is the opposite of boxing process where the reference type is converted to a value type.
Q47. What is Code Access security? What is CAS in .NET?
Ans. CAS is the feature of the .NET security model that determines whether an application or a piece of code is permitted to run and decide the resources it can use while running.
Q48. What is Multi-tasking?
Ans. It is a feature of operating systems through which multiple programs may run on the operating system at the same time, just like a scenario where a Notepad, a Calculator and the Control Panel are open at the same time.
Q49. What is Multi-threading?
Ans. When an application performs different tasks at the same time, the application is said to exhibit multithreading as several threads of a process are running.2
Q50. What is a Thread?
Ans. A thread is an activity started by a process and its the basic unit to which an operating system allocates processor resources.
Q51. What does AddressOf in VB.NET operator do?
Ans. The AddressOf operator is used in VB.NET to create a delegate object to a method in order to point to it.
Q52. How to refer to the current thread of a method in .NET?
Ans. In order to refer to the current thread in .NET, the Thread.CurrentThread method can be used. It is a public static property.
Q53. How to pause the execution of a thread in .NET?
Ans. The thread execution can be paused by invoking the Thread.Sleep(IntegerValue) method where IntegerValue is an integer that determines the milliseconds time frame for which the thread in context has to sleep.
Q54. How can we force a thread to sleep for an infinite period?
Ans. Call the Thread.Interupt() method.
Q55. What is Suspend and Resume in .NET Threading?
Ans. Just like a song may be paused and played using a music player, a thread may be paused using Thread.Suspend method and may be started again using the Thread.Resume method. Note that sleep method immediately forces the thread to sleep whereas the suspend method waits for the thread to be in a persistable position before pausing its activity.
Q56. How can we prevent a deadlock in .Net threading?
Ans. Using methods like Monitoring, Interlocked classes, Wait handles, Event raising from between threads, using the ThreadState property.
Q57. What is Ajax?
Ans. Asyncronous Javascript and XML - Ajax is a combination of client side technologies that sets up asynchronous communication between the user interface and the web server so that partial page rendering occur instead of complete page postbacks.
Q58. What is XmlHttpRequest in Ajax?
Ans. It is an object in Javascript that allows the browser to communicate to a web server asynchronously without making a postback.
Q59. What are the different modes of storing an ASP.NET session?
Ans. InProc (the session state is stored in the memory space of the Aspnet_wp.exe process but the session information is lost when IIS reboots), StateServer (the Session state is serialized and stored in a separate process call Viewstate is an object in .NET that automatically persists control setting values across the multiple requests for the same page and it is internally maintained as a hidden field on the web page though its hashed for security reasons.
Q60. What is a delegate in .NET?
Ans. A delegate in .NET is a class that can have a reference to a method, and this class has a signature that can refer only those methods that have a signature which complies with the class.
Ans. We may call the garbage collector to collect unreferenced data by executing the System.GC.Collect() method.
Q42. How can we set the Focus on a control in ASP.NET?
Ans. txtBox123.Focus(); OR Page.SetFocus(NameOfControl);
Q43. What are Partial Classes in Asp.Net 2.0?
Ans. In .NET 2.0, a class definition may be split into multiple physical files but partial classes do not make any difference to the compiler as during compile time, the compiler groups all the partial classes and treats them as a single class.
Q44. How to set the default button on a Web Form?
Ans.
Q45.Can we force the garbage collector to run?
Ans. Yes, using the System.GC.Collect(), the garbage collector is forced to run in case required to do so.
Q46. What is Boxing and Unboxing?
Ans. Boxing is the process where any value type can be implicitly converted to a reference type object while Unboxing is the opposite of boxing process where the reference type is converted to a value type.
Q47. What is Code Access security? What is CAS in .NET?
Ans. CAS is the feature of the .NET security model that determines whether an application or a piece of code is permitted to run and decide the resources it can use while running.
Q48. What is Multi-tasking?
Ans. It is a feature of operating systems through which multiple programs may run on the operating system at the same time, just like a scenario where a Notepad, a Calculator and the Control Panel are open at the same time.
Q49. What is Multi-threading?
Ans. When an application performs different tasks at the same time, the application is said to exhibit multithreading as several threads of a process are running.2
Q50. What is a Thread?
Ans. A thread is an activity started by a process and its the basic unit to which an operating system allocates processor resources.
Q51. What does AddressOf in VB.NET operator do?
Ans. The AddressOf operator is used in VB.NET to create a delegate object to a method in order to point to it.
Q52. How to refer to the current thread of a method in .NET?
Ans. In order to refer to the current thread in .NET, the Thread.CurrentThread method can be used. It is a public static property.
Q53. How to pause the execution of a thread in .NET?
Ans. The thread execution can be paused by invoking the Thread.Sleep(IntegerValue) method where IntegerValue is an integer that determines the milliseconds time frame for which the thread in context has to sleep.
Q54. How can we force a thread to sleep for an infinite period?
Ans. Call the Thread.Interupt() method.
Q55. What is Suspend and Resume in .NET Threading?
Ans. Just like a song may be paused and played using a music player, a thread may be paused using Thread.Suspend method and may be started again using the Thread.Resume method. Note that sleep method immediately forces the thread to sleep whereas the suspend method waits for the thread to be in a persistable position before pausing its activity.
Q56. How can we prevent a deadlock in .Net threading?
Ans. Using methods like Monitoring, Interlocked classes, Wait handles, Event raising from between threads, using the ThreadState property.
Q57. What is Ajax?
Ans. Asyncronous Javascript and XML - Ajax is a combination of client side technologies that sets up asynchronous communication between the user interface and the web server so that partial page rendering occur instead of complete page postbacks.
Q58. What is XmlHttpRequest in Ajax?
Ans. It is an object in Javascript that allows the browser to communicate to a web server asynchronously without making a postback.
Q59. What are the different modes of storing an ASP.NET session?
Ans. InProc (the session state is stored in the memory space of the Aspnet_wp.exe process but the session information is lost when IIS reboots), StateServer (the Session state is serialized and stored in a separate process call Viewstate is an object in .NET that automatically persists control setting values across the multiple requests for the same page and it is internally maintained as a hidden field on the web page though its hashed for security reasons.
Q60. What is a delegate in .NET?
Ans. A delegate in .NET is a class that can have a reference to a method, and this class has a signature that can refer only those methods that have a signature which complies with the class.
Short Answer .NET Interview Questions (PAGE 2)
Q21. What is encapsulation?
Ans. Encapsulation is the OOPs concept of binding the attributes and behaviors in a class, hiding the implementation of the class and exposing the functionality.
Q22. What is Overloading?
Ans. When we add a new method with the same name in a same/derived class but with different number/types of parameters, the concept is called overluoad and this ultimately implements Polymorphism.
Q23. What is Overriding?
Ans. When we need to provide different implementation in a child class than the one provided by base class, we define the same method with same signatures in the child class and this is called overriding.
Q24. What is a Delegate?
Ans. A delegate is a strongly typed function pointer object that encapsulates a reference to a method, and so the function that needs to be invoked may be called at runtime.
Q25. Is String a Reference Type or Value Type in .NET?
Ans. String is a Reference Type object.
Q26. What is a Satellite Assembly?
Ans. Satellite assemblies contain resource files corresponding to a locale (Culture + Language) and these assemblies are used in deploying an application globally for different languages.
Q27. What are the different types of assemblies and what is their use?
Ans. Private, Public(also called shared) and Satellite Assemblies.
Q28. Are MSIL and CIL the same thing?
Ans. Yes, CIL is the new name for MSIL.
Q29. What is the base class of all web forms?
Ans. System.Web.UI.Page
Q30. How to add a client side event to a server control?
Ans. Example... BtnSubmit.Attributes.Add("onclick","javascript:fnSomeFunctionInJavascript()");
Q31. How to register a client side script from code-behind?
Ans. Use the Page.RegisterClientScriptBlock method in the server side code to register the script that may be built using a StringBuilder.
Q32. Can a single .NET DLL contain multiple classes?
Ans. Yes, a single .NET DLL may contain any number of classes within it.
Q33. What is DLL Hell?
Ans. DLL Hell is the name given to the problem of old unmanaged DLL's due to which there was a possibility of version conflict among the DLLs.
Q34. can we put a break statement in a finally block?
Ans. The finally block cannot have the break, continue, return and goto statements.
Q35. What is a CompositeControl in .NET?
Ans. CompositeControl is an abstract class in .NET that is inherited by those web controls that contain child controls within them.
Q36. Which control in asp.net is used to display data from an xml file and then displayed using XSLT?
Ans. Use the asp:Xml control and set its DocumentSource property for associating an xml file, and set its TransformSource property to set the xml control's xsl file for the XSLT transformation.
Q37. Can we run ASP.NET 1.1 application and ASP.NET 2.0 application on the same computer?
Ans. Yes, though changes in the IIS in the properties for the site have to be made during deployment of each.
Q38. What are the new features in .NET 2.0?
Ans. Plenty of new controls, Generics, anonymous methods, partial classes, iterators, property visibility (separate visibility for get and set) and static classes.
Q39. Can we pop a MessageBox in a web application?
Ans. Yes, though this is done clientside using an alert, prompt or confirm or by opening a new web page that looks like a messagebox.
Q40. What is managed data?
Ans. The data for which the memory management is taken care by .Net runtime’s garbage collector, and this includes tasks for allocation de-allocation.
Ans. Encapsulation is the OOPs concept of binding the attributes and behaviors in a class, hiding the implementation of the class and exposing the functionality.
Q22. What is Overloading?
Ans. When we add a new method with the same name in a same/derived class but with different number/types of parameters, the concept is called overluoad and this ultimately implements Polymorphism.
Q23. What is Overriding?
Ans. When we need to provide different implementation in a child class than the one provided by base class, we define the same method with same signatures in the child class and this is called overriding.
Q24. What is a Delegate?
Ans. A delegate is a strongly typed function pointer object that encapsulates a reference to a method, and so the function that needs to be invoked may be called at runtime.
Q25. Is String a Reference Type or Value Type in .NET?
Ans. String is a Reference Type object.
Q26. What is a Satellite Assembly?
Ans. Satellite assemblies contain resource files corresponding to a locale (Culture + Language) and these assemblies are used in deploying an application globally for different languages.
Q27. What are the different types of assemblies and what is their use?
Ans. Private, Public(also called shared) and Satellite Assemblies.
Q28. Are MSIL and CIL the same thing?
Ans. Yes, CIL is the new name for MSIL.
Q29. What is the base class of all web forms?
Ans. System.Web.UI.Page
Q30. How to add a client side event to a server control?
Ans. Example... BtnSubmit.Attributes.Add("onclick","javascript:fnSomeFunctionInJavascript()");
Q31. How to register a client side script from code-behind?
Ans. Use the Page.RegisterClientScriptBlock method in the server side code to register the script that may be built using a StringBuilder.
Q32. Can a single .NET DLL contain multiple classes?
Ans. Yes, a single .NET DLL may contain any number of classes within it.
Q33. What is DLL Hell?
Ans. DLL Hell is the name given to the problem of old unmanaged DLL's due to which there was a possibility of version conflict among the DLLs.
Q34. can we put a break statement in a finally block?
Ans. The finally block cannot have the break, continue, return and goto statements.
Q35. What is a CompositeControl in .NET?
Ans. CompositeControl is an abstract class in .NET that is inherited by those web controls that contain child controls within them.
Q36. Which control in asp.net is used to display data from an xml file and then displayed using XSLT?
Ans. Use the asp:Xml control and set its DocumentSource property for associating an xml file, and set its TransformSource property to set the xml control's xsl file for the XSLT transformation.
Q37. Can we run ASP.NET 1.1 application and ASP.NET 2.0 application on the same computer?
Ans. Yes, though changes in the IIS in the properties for the site have to be made during deployment of each.
Q38. What are the new features in .NET 2.0?
Ans. Plenty of new controls, Generics, anonymous methods, partial classes, iterators, property visibility (separate visibility for get and set) and static classes.
Q39. Can we pop a MessageBox in a web application?
Ans. Yes, though this is done clientside using an alert, prompt or confirm or by opening a new web page that looks like a messagebox.
Q40. What is managed data?
Ans. The data for which the memory management is taken care by .Net runtime’s garbage collector, and this includes tasks for allocation de-allocation.
Short Answer .NET Interview Questions (PAGE 1)
Q1. Explain the differences between Server-side and Client-side code?
Ans. Server side code will execute at server (where the website is hosted) end, & all the business logic will execute at server end where as client side code will execute at client side (usually written in javascript, vbscript, jscript) at browser end.
Q2. What type of code (server or client) is found in a Code-Behind class?
Ans. Server side code.
Q3. How to make sure that value is entered in an asp:Textbox control?
Ans. Use a RequiredFieldValidator control.
Q4. Which property of a validation control is used to associate it with a server control on that page?
Ans. ControlToValidate property.
Q5. How would you implement inheritance using VB.NET & C#?
Ans. C# Derived Class : Baseclass
VB.NEt : Derived Class Inherits Baseclass
Q6. Which method is invoked on the DataAdapter control to load the generated dataset with data?
Ans. Fill() method.
Q7. What method is used to explicitly kill a user's session?
Ans. Session.Abandon()
Q8. What property within the asp:gridview control is changed to bind columns manually?
Ans. Autogenerated columns is set to false
Q9. Which method is used to redirect the user to another page without performing a round trip to the client?
Ans. Server.Transfer method.
Q10. How do we use different versions of private assemblies in same application without re-build?
Ans.Inside the Assemblyinfo.cs or Assemblyinfo.vb file, we need to specify assembly version.
assembly: AssemblyVersion
Q11. Is it possible to debug java-script in .NET IDE? If yes, how?
Ans. Yes, simply write "debugger" statement at the point where the breakpoint needs to be set within the javascript code and also enable javascript debugging in the browser property settings.
Q12. How many ways can we maintain the state of a page?
Ans. 1. Client Side - Query string, hidden variables, viewstate, cookies
2. Server side - application , cache, context, session, database
Q13. What is the use of a multicast delegate?
Ans. A multicast delegate may be used to call more than one method.
Q14. What is the use of a private constructor?
Ans. A private constructor may be used to prevent the creation of an instance for a class.
Q15. What is the use of Singleton pattern?
Ans. A Singleton pattern .is used to make sure that only one instance of a class exists.
Q16. When do we use a DOM parser and when do we use a SAX parser?
Ans. The DOM Approach is useful for small documents in which the program needs to process a large portion of the document whereas the SAX approach is useful for large documents in which the program only needs to process a small portion of the document.
Q17. Will the finally block be executed if an exception has not occurred?
Ans.Yes it will execute.
Q18. What is a Dataset?
Ans. A dataset is an in memory database kindof object that can hold database information in a disconnected environment.
Q19. Is XML a case-sensitive markup language?
Ans. Yes.
Q20. What is an .ashx file?
Ans. It is a web handler file that produces output to be consumed by an xml consumer client (rather than a browser).
Ans. Server side code will execute at server (where the website is hosted) end, & all the business logic will execute at server end where as client side code will execute at client side (usually written in javascript, vbscript, jscript) at browser end.
Q2. What type of code (server or client) is found in a Code-Behind class?
Ans. Server side code.
Q3. How to make sure that value is entered in an asp:Textbox control?
Ans. Use a RequiredFieldValidator control.
Q4. Which property of a validation control is used to associate it with a server control on that page?
Ans. ControlToValidate property.
Q5. How would you implement inheritance using VB.NET & C#?
Ans. C# Derived Class : Baseclass
VB.NEt : Derived Class Inherits Baseclass
Q6. Which method is invoked on the DataAdapter control to load the generated dataset with data?
Ans. Fill() method.
Q7. What method is used to explicitly kill a user's session?
Ans. Session.Abandon()
Q8. What property within the asp:gridview control is changed to bind columns manually?
Ans. Autogenerated columns is set to false
Q9. Which method is used to redirect the user to another page without performing a round trip to the client?
Ans. Server.Transfer method.
Q10. How do we use different versions of private assemblies in same application without re-build?
Ans.Inside the Assemblyinfo.cs or Assemblyinfo.vb file, we need to specify assembly version.
assembly: AssemblyVersion
Q11. Is it possible to debug java-script in .NET IDE? If yes, how?
Ans. Yes, simply write "debugger" statement at the point where the breakpoint needs to be set within the javascript code and also enable javascript debugging in the browser property settings.
Q12. How many ways can we maintain the state of a page?
Ans. 1. Client Side - Query string, hidden variables, viewstate, cookies
2. Server side - application , cache, context, session, database
Q13. What is the use of a multicast delegate?
Ans. A multicast delegate may be used to call more than one method.
Q14. What is the use of a private constructor?
Ans. A private constructor may be used to prevent the creation of an instance for a class.
Q15. What is the use of Singleton pattern?
Ans. A Singleton pattern .is used to make sure that only one instance of a class exists.
Q16. When do we use a DOM parser and when do we use a SAX parser?
Ans. The DOM Approach is useful for small documents in which the program needs to process a large portion of the document whereas the SAX approach is useful for large documents in which the program only needs to process a small portion of the document.
Q17. Will the finally block be executed if an exception has not occurred?
Ans.Yes it will execute.
Q18. What is a Dataset?
Ans. A dataset is an in memory database kindof object that can hold database information in a disconnected environment.
Q19. Is XML a case-sensitive markup language?
Ans. Yes.
Q20. What is an .ashx file?
Ans. It is a web handler file that produces output to be consumed by an xml consumer client (rather than a browser).
VB.NET Interview Questions 16
What is a delegate, why should you use it and how do you call it ?
A delegate is a reference type that refers to a Shared method of a type or to an instance method of an object. Delegate is like a function pointer in C and C++. Pointers are used to store the address of a thing. Delegate lets some other code call your function without needing to know where your function is actually located. All events in .NET actually use delegates in the background to wire up events. Events are really just a modified form of a delegate.
It should give you an idea of some different areas in which delegates may be appropriate:
1.They enable callback functionality in multi-tier applications as demonstrated in the examples above.
2.The CacheItemRemoveCallback delegate can be used in ASP.NET to keep cached information up to date. When the cached information is removed for any reason, the associated callback is exercised and could contain a reload of the cached information.
3. Use delegates to facilitate asynchronous processing for methods that do not offer asynchronous behavior.
4.Events use delegates so clients can give the application events to call when the event is fired. Exposing custom events within your applications requires the use of delegates.
How does the XmlSerializer work?
XmlSerializer in the .NET Framework is a great tool to convert Xml into runtime objects and vice versa
If you define integer variable and a object variable and a structure then how those will be plotted in memory.
Integer , structure - System.ValueType -- Allocated memory on stack , infact integer is primitive type recognized and allocated memory by compiler itself .
Infact , System.Int32 definition is as follows :
[C#]
[Serializable]
public struct Int32 : IComparable, IFormattable, IConvertible
So , it's a struct by definition , which is the same case with various other value types .
Object - Base class , that is by default reference type , so at runtime JIT compiler allocates memory on the "Heap" Data structure .
Reference types are defined as class , derived directly or indirectly by System.ReferenceType
A delegate is a reference type that refers to a Shared method of a type or to an instance method of an object. Delegate is like a function pointer in C and C++. Pointers are used to store the address of a thing. Delegate lets some other code call your function without needing to know where your function is actually located. All events in .NET actually use delegates in the background to wire up events. Events are really just a modified form of a delegate.
It should give you an idea of some different areas in which delegates may be appropriate:
1.They enable callback functionality in multi-tier applications as demonstrated in the examples above.
2.The CacheItemRemoveCallback delegate can be used in ASP.NET to keep cached information up to date. When the cached information is removed for any reason, the associated callback is exercised and could contain a reload of the cached information.
3. Use delegates to facilitate asynchronous processing for methods that do not offer asynchronous behavior.
4.Events use delegates so clients can give the application events to call when the event is fired. Exposing custom events within your applications requires the use of delegates.
How does the XmlSerializer work?
XmlSerializer in the .NET Framework is a great tool to convert Xml into runtime objects and vice versa
If you define integer variable and a object variable and a structure then how those will be plotted in memory.
Integer , structure - System.ValueType -- Allocated memory on stack , infact integer is primitive type recognized and allocated memory by compiler itself .
Infact , System.Int32 definition is as follows :
[C#]
[Serializable]
public struct Int32 : IComparable, IFormattable, IConvertible
So , it's a struct by definition , which is the same case with various other value types .
Object - Base class , that is by default reference type , so at runtime JIT compiler allocates memory on the "Heap" Data structure .
Reference types are defined as class , derived directly or indirectly by System.ReferenceType
VB.NET Interview Questions 15
what an array is?
The dictionary meaning of array is an orderly arrangement or sequential arrangement of elements.
In computer science term:
An array is a data structure that contains a number of variables, which are accessed through computed indices. The variables contained in an array, also called the elements of the array, are all of the same type, and this type is called the element type of the array.
An array has a rank that determines the number of indices associated with each array element. The rank of an array is also referred to as the dimensions of the array. An array with a rank of one is called a single-dimensional array. An array with a rank greater than one is called a multi-dimensional array. Specific sized multidimensional arrays are often referred to as two-dimensional arrays, three-dimensional arrays, and so on.
What are jagged arrays?
A jagged array is an array whose elements are arrays. The elements of jagged array can be of different dimensions and sizes. A jagged array is sometimes called as "array-of-arrays". It is called jagged because each of its rows is of different size so the final or graphical representation is not a square.
When you create a jagged array you declare the number of rows in your array. Each row will hold an array that will be on any length. Before filling the values in the inner arrays you must declare them.
Jagged array declaration in C#:
For e.g. : int [] [] myJaggedArray = new int [3][];
Declaration of inner arrays:
myJaggedArray[0] = new int[5] ; // First inner array will be of length 5.
myJaggedArray[1] = new int[4] ; // Second inner array will be of length 4.
myJaggedArray[2] = new int[3] ; // Third inner array will be of length 3.
Now to access third element of second row we write:
int value = myJaggedArray[1][2];
Note that while declaring the array the second dimension is not supplied because this you will declare later on in the code.
Jagged array are created out of single dimensional arrays so be careful while using them. Don't confuse it with multi-dimensional arrays because unlike them jagged arrays are not rectangular arrays.
For more information on arrays:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/csref/html/vclrfarrayspg.asp
The dictionary meaning of array is an orderly arrangement or sequential arrangement of elements.
In computer science term:
An array is a data structure that contains a number of variables, which are accessed through computed indices. The variables contained in an array, also called the elements of the array, are all of the same type, and this type is called the element type of the array.
An array has a rank that determines the number of indices associated with each array element. The rank of an array is also referred to as the dimensions of the array. An array with a rank of one is called a single-dimensional array. An array with a rank greater than one is called a multi-dimensional array. Specific sized multidimensional arrays are often referred to as two-dimensional arrays, three-dimensional arrays, and so on.
What are jagged arrays?
A jagged array is an array whose elements are arrays. The elements of jagged array can be of different dimensions and sizes. A jagged array is sometimes called as "array-of-arrays". It is called jagged because each of its rows is of different size so the final or graphical representation is not a square.
When you create a jagged array you declare the number of rows in your array. Each row will hold an array that will be on any length. Before filling the values in the inner arrays you must declare them.
Jagged array declaration in C#:
For e.g. : int [] [] myJaggedArray = new int [3][];
Declaration of inner arrays:
myJaggedArray[0] = new int[5] ; // First inner array will be of length 5.
myJaggedArray[1] = new int[4] ; // Second inner array will be of length 4.
myJaggedArray[2] = new int[3] ; // Third inner array will be of length 3.
Now to access third element of second row we write:
int value = myJaggedArray[1][2];
Note that while declaring the array the second dimension is not supplied because this you will declare later on in the code.
Jagged array are created out of single dimensional arrays so be careful while using them. Don't confuse it with multi-dimensional arrays because unlike them jagged arrays are not rectangular arrays.
For more information on arrays:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/csref/html/vclrfarrayspg.asp
VB.NET Interview Questions 14
Does C# support multiple inheritance?
No, use interfaces instead.
So how do you retrieve the customized properties of a .NET application from XML .config file? Can you automate this process?
Initialize an instance of AppSettingsReader class. Call the GetValue method of AppSettingsReader class, passing in the name of the property and the type expected. Assign the result to the appropriate variable. In Visual Studio yes, use Dynamic Properties for automatic .config creation, storage and retrieval.
No, use interfaces instead.
So how do you retrieve the customized properties of a .NET application from XML .config file? Can you automate this process?
Initialize an instance of AppSettingsReader class. Call the GetValue method of AppSettingsReader class, passing in the name of the property and the type expected. Assign the result to the appropriate variable. In Visual Studio yes, use Dynamic Properties for automatic .config creation, storage and retrieval.
VB.NET Interview Questions 13
Does C# support multiple inheritance?
No, use interfaces instead.
So how do you retrieve the customized properties of a .NET application from XML .config file? Can you automate this process?
Initialize an instance of AppSettingsReader class. Call the GetValue method of AppSettingsReader class, passing in the name of the property and the type expected. Assign the result to the appropriate variable. In Visual Studio yes, use Dynamic Properties for automatic .config creation, storage and retrieval.
No, use interfaces instead.
So how do you retrieve the customized properties of a .NET application from XML .config file? Can you automate this process?
Initialize an instance of AppSettingsReader class. Call the GetValue method of AppSettingsReader class, passing in the name of the property and the type expected. Assign the result to the appropriate variable. In Visual Studio yes, use Dynamic Properties for automatic .config creation, storage and retrieval.
VB.NET Interview Questions 12
What's the implicit name of the parameter that gets passed into the class' set method?
Value, and it's datatype depends on whatever variable we're changing.
How do you inherit from a class in C#?
Place a colon and then the name of the base class. Notice that it's double colon in C++.
Value, and it's datatype depends on whatever variable we're changing.
How do you inherit from a class in C#?
Place a colon and then the name of the base class. Notice that it's double colon in C++.
VB.NET Interview Questions 11
How do you generate documentation from the C# file commented properly with a command-line compiler?
Compile it with a /doc switch.
Can you change the value of a variable while debugging a C# application?
Yes, if you are debugging via Visual Studio.NET, just go to Immediate window.
Compile it with a /doc switch.
Can you change the value of a variable while debugging a C# application?
Yes, if you are debugging via Visual Studio.NET, just go to Immediate window.
VB.NET Interview Questions
Can multiple catch blocks be executed?
No, once the proper catch code fires off, the control is transferred to the finally block (if there are any), and then whatever follows the finally block.
Why is it a bad idea to throw your own exceptions?
Well, if at that point you know that an error has occurred, then why not write the proper code to handle that error instead of passing a new Exception object to the catch block? Throwing your own exceptions signifies some design flaws in the project.
What's the difference between // comments, /* */ comments and /// comments?
Single-line, multi-line and XML documentation comments.
No, once the proper catch code fires off, the control is transferred to the finally block (if there are any), and then whatever follows the finally block.
Why is it a bad idea to throw your own exceptions?
Well, if at that point you know that an error has occurred, then why not write the proper code to handle that error instead of passing a new Exception object to the catch block? Throwing your own exceptions signifies some design flaws in the project.
What's the difference between // comments, /* */ comments and /// comments?
Single-line, multi-line and XML documentation comments.
VB.NET Interview Questions 9
Will finally block get executed if the exception had not occurred?
Yes.
What's the C# equivalent of C++ catch (...), which was a catch-all statement for any possible exception?
A catch block that catches the exception of type System.Exception. You can also omit the parameter data type in this case and just write catch {}.
Yes.
What's the C# equivalent of C++ catch (...), which was a catch-all statement for any possible exception?
A catch block that catches the exception of type System.Exception. You can also omit the parameter data type in this case and just write catch {}.
VB.NET Interview Questions 8
What happens when you encounter a continue statement inside the for loop?
The code for the rest of the loop is ignored, the control is transferred back to the beginning of the loop.
How can you sort the elements of the array in descending order?
By calling Sort() and then Reverse() methods.
The code for the rest of the loop is ignored, the control is transferred back to the beginning of the loop.
How can you sort the elements of the array in descending order?
By calling Sort() and then Reverse() methods.
VB.NET Interview Questions 6
How do you convert a string into an integer in .NET?
Int32.Parse(string)
Can you declare a C++ type destructor in C# like ~MyClass()?
Yes, but what's the point, since it will call Finalize(), and Finalize() has no guarantees when the memory will be cleaned up, plus, it introduces additional load on the garbage collector.
What's different about namespace declaration when comparing that to package declaration in Java?
No semicolon.
What's the difference between const and readonly?
The readonly keyword is different from the const keyword. A const field can only be initialized at the declaration of the field. A readonly field can be initialized either at the declaration or in a constructor. Therefore, readonly fields can have different values depending on the constructor used. Also, while a const field is a compile-time constant, the readonly field can be used for runtime constants as in the following example:
public static readonly uint l1 = (uint) DateTime.Now.Ticks;
What does a character do?
On most systems, produces a rather annoying beep.
Int32.Parse(string)
Can you declare a C++ type destructor in C# like ~MyClass()?
Yes, but what's the point, since it will call Finalize(), and Finalize() has no guarantees when the memory will be cleaned up, plus, it introduces additional load on the garbage collector.
What's different about namespace declaration when comparing that to package declaration in Java?
No semicolon.
What's the difference between const and readonly?
The readonly keyword is different from the const keyword. A const field can only be initialized at the declaration of the field. A readonly field can be initialized either at the declaration or in a constructor. Therefore, readonly fields can have different values depending on the constructor used. Also, while a const field is a compile-time constant, the readonly field can be used for runtime constants as in the following example:
public static readonly uint l1 = (uint) DateTime.Now.Ticks;
What does a character do?
On most systems, produces a rather annoying beep.
VB.NET Interview Questions 5
Why is the XML InfoSet specification different from the Xml DOM? What does the InfoSet attempt to solve?
"The XML Information Set (Infoset) defines a data model for XML. The Infoset describes the abstract representation of an XML Document. Infoset is the generalized representation of the XML Document, which is primarily meant to act as a set of definitions used by XML technologies to formally describe what parts of an XML document they operate upon.
The Document Object Model (DOM) is one technology for representing an XML Document in memory and to programmatically read, modify and manipulate a xml document.
Infoset helps defining generalized standards on how to use XML that is not dependent or tied to a particular XML specification or API. The Infoset tells us what part of XML Document should be considered as significant information.
Contrast DTDs versus XSDs. What are their similarities and differences? Which is preferred and why?
Document Type Definition (DTD) describes a model or set of rules for an XML document. XML Schema Definition (XSD) also describes the structure of an XML document but XSDs are much more powerful.
The disadvantage with the Document Type Definition is it doesn't support data types beyond the basic 10 primitive types. It cannot properly define the type of data contained by the tag.
An Xml Schema provides an Object Oriented approach to defining the format of an xml document. The Xml schema support most basic programming types like integer, byte, string, float etc., We can also define complex types of our own which can be used to define a xml document.
Xml Schemas are always preferred over DTDs as a document can be more precisely defined using the XML Schemas because of its rich support for data representation.
Speaking of Boolean data types, what's different between C# and C/C++?
There's no conversion between 0 and false, as well as any other number and true, like in C/C++.
"The XML Information Set (Infoset) defines a data model for XML. The Infoset describes the abstract representation of an XML Document. Infoset is the generalized representation of the XML Document, which is primarily meant to act as a set of definitions used by XML technologies to formally describe what parts of an XML document they operate upon.
The Document Object Model (DOM) is one technology for representing an XML Document in memory and to programmatically read, modify and manipulate a xml document.
Infoset helps defining generalized standards on how to use XML that is not dependent or tied to a particular XML specification or API. The Infoset tells us what part of XML Document should be considered as significant information.
Contrast DTDs versus XSDs. What are their similarities and differences? Which is preferred and why?
Document Type Definition (DTD) describes a model or set of rules for an XML document. XML Schema Definition (XSD) also describes the structure of an XML document but XSDs are much more powerful.
The disadvantage with the Document Type Definition is it doesn't support data types beyond the basic 10 primitive types. It cannot properly define the type of data contained by the tag.
An Xml Schema provides an Object Oriented approach to defining the format of an xml document. The Xml schema support most basic programming types like integer, byte, string, float etc., We can also define complex types of our own which can be used to define a xml document.
Xml Schemas are always preferred over DTDs as a document can be more precisely defined using the XML Schemas because of its rich support for data representation.
Speaking of Boolean data types, what's different between C# and C/C++?
There's no conversion between 0 and false, as well as any other number and true, like in C/C++.
VB.NET Interview Questions 4
What is the difference between an XML "Fragment" and an XML "Document."
An XML fragment is an XML document with no single top-level root element. To put it simple it is a part (fragment) of a well-formed xml document. (node) Where as a well-formed xml document must have only one root element.
What does it meant to say "the canonical" form of XML?
"The purpose of Canonical XML is to define a standard format for an XML document. Canonical XML is a very strict XML syntax, which lets documents in canonical XML be compared directly.
Using this strict syntax makes it easier to see whether two XML documents are the same. For example, a section of text in one document might read Black & White, whereas the same section of text might read Black & White in another document, and even in another. If you compare those three documents byte by byte, they'll be different. But if you write them all in canonical XML, which specifies every aspect of the syntax you can use, these three documents would all have the same version of this text (which would be Black & White) and could be compared without problem.
This Comparison is especially critical when xml documents are digitally signed. The digital signal may be interpreted in different way and the document may be rejected.
An XML fragment is an XML document with no single top-level root element. To put it simple it is a part (fragment) of a well-formed xml document. (node) Where as a well-formed xml document must have only one root element.
What does it meant to say "the canonical" form of XML?
"The purpose of Canonical XML is to define a standard format for an XML document. Canonical XML is a very strict XML syntax, which lets documents in canonical XML be compared directly.
Using this strict syntax makes it easier to see whether two XML documents are the same. For example, a section of text in one document might read Black & White, whereas the same section of text might read Black & White in another document, and even in another. If you compare those three documents byte by byte, they'll be different. But if you write them all in canonical XML, which specifies every aspect of the syntax you can use, these three documents would all have the same version of this text (which would be Black & White) and could be compared without problem.
This Comparison is especially critical when xml documents are digitally signed. The digital signal may be interpreted in different way and the document may be rejected.
VB.NET Interview Questions 3
How is a property designated as read-only?
In VB.NET:
Private mPropertyName as DataType
Public ReadOnly Property PropertyName() As DataType
Get Return mPropertyName
End Get
End Property
In C#
Private DataType mPropertyName;
public returntype PropertyName
{
get{
//property implementation goes here
return mPropertyName;
}
// Do not write the set implementation
}
What is hiding in CSharp ?
Hiding is also called as Shadowing. This is the concept of Overriding the methods. It is a concept used in the Object Oriented Programming.
E.g.
public class ClassA {
public virtual void MethodA() {
Trace.WriteLine("ClassA Method");
}
}
public class ClassB : ClassA {
public new void MethodA() {
Trace.WriteLine("SubClass ClassB Method");
}
}
public class TopLevel {
static void Main(string[] args) {
TextWriter tw = Console.Out;
Trace.Listeners.Add(new TextWriterTraceListener(tw));
ClassA obj = new ClassB();
obj.MethodA(); // Outputs "Class A Method"
ClassB obj1 = new ClassB();
obj.MethodA(); // Outputs "SubClass ClassB Method"
}
}
In VB.NET:
Private mPropertyName as DataType
Public ReadOnly Property PropertyName() As DataType
Get Return mPropertyName
End Get
End Property
In C#
Private DataType mPropertyName;
public returntype PropertyName
{
get{
//property implementation goes here
return mPropertyName;
}
// Do not write the set implementation
}
What is hiding in CSharp ?
Hiding is also called as Shadowing. This is the concept of Overriding the methods. It is a concept used in the Object Oriented Programming.
E.g.
public class ClassA {
public virtual void MethodA() {
Trace.WriteLine("ClassA Method");
}
}
public class ClassB : ClassA {
public new void MethodA() {
Trace.WriteLine("SubClass ClassB Method");
}
}
public class TopLevel {
static void Main(string[] args) {
TextWriter tw = Console.Out;
Trace.Listeners.Add(new TextWriterTraceListener(tw));
ClassA obj = new ClassB();
obj.MethodA(); // Outputs "Class A Method"
ClassB obj1 = new ClassB();
obj.MethodA(); // Outputs "SubClass ClassB Method"
}
}
VB.NET Interview Questions 2
How would you implement inheritance using VB.NET/C#?
When we set out to implement a class using inheritance, we must first start with an existing class from which we will derive our new subclass. This existing class, or base class, may be part of the .NET system class library framework, it may be part of some other application or .NET assembly, or we may create it as part of our existing application. Once we have a base class, we can then implement one or more subclasses based on that base class. Each of our subclasses will automatically have all of the methods, properties, and events of that base class ? including the implementation behind each method, property, and event. Our subclass can add new methods, properties, and events of its own - extending the original interface with new functionality. Additionally, a subclass can replace the methods and properties of the base class with its own new
implementation - effectively overriding the original behavior and replacing it with new behaviors. Essentially inheritance is a way of merging functionality from an existing class into our new subclass. Inheritance also defines rules for how these methods, properties, and events can be merged. In VB.NET we can use implements keyword for inheritance, while in C# we can use the sign ( :: ) between subclass and baseclass.
When we set out to implement a class using inheritance, we must first start with an existing class from which we will derive our new subclass. This existing class, or base class, may be part of the .NET system class library framework, it may be part of some other application or .NET assembly, or we may create it as part of our existing application. Once we have a base class, we can then implement one or more subclasses based on that base class. Each of our subclasses will automatically have all of the methods, properties, and events of that base class ? including the implementation behind each method, property, and event. Our subclass can add new methods, properties, and events of its own - extending the original interface with new functionality. Additionally, a subclass can replace the methods and properties of the base class with its own new
implementation - effectively overriding the original behavior and replacing it with new behaviors. Essentially inheritance is a way of merging functionality from an existing class into our new subclass. Inheritance also defines rules for how these methods, properties, and events can be merged. In VB.NET we can use implements keyword for inheritance, while in C# we can use the sign ( :: ) between subclass and baseclass.
VB.NET Interview Questions 1
Explain the differences between Server-side and Client-side code?
Server side code executes on the server.For this to occur page has to be submitted or posted back.Events fired by the controls are executed on the server.Client side code executes in the browser of the client without submitting the page.
e.g. In ASP.NET for webcontrols like asp:button the click event of the button is executed on the server hence the event handler for the same in a part of the code-behind (server-side code). Along the server-side code events one can also attach client side events which are executed in the clients browser i.e. javascript events.
How does VB.NET/C# achieve polymorphism?
Polymorphism is also achieved through interfaces. Like abstract classes, interfaces also describe the methods that a class needs to implement. The difference between abstract classes and interfaces is that abstract classes always act as a base class of the related classes in the class hierarchy. For example, consider a hierarchy-car and truck classes derived from four-wheeler class; the classes two-wheeler and four-wheeler derived from an abstract class vehicle. So, the class 'vehicle' is the base class in the class hierarchy. On the other hand dissimilar classes can implement one interface. For example, there is an interface that compares two objects. This interface can be implemented by the classes like box, person and string, which are unrelated to each other.
C# allows multiple interface inheritance. It means that a class can implement more than one interface. The methods declared in an interface are implicitly abstract. If a class implements an interface, it becomes mandatory for the class to override all the methods declared in the interface, otherwise the derived class would become abstract.
Can you explain what inheritance is and an example of when you might use it?
The savingaccount class has two data members-accno that stores account number, and trans that keeps track of the number of transactions. We can create an object of savingaccount class as shown below.
savingaccount s = new savingaccount ( "Amar", 5600.00f ) ;
From the constructor of savingaccount class we have called the two-argument constructor of the account class using the base keyword and passed the name and balance to this constructor using which the data member's name and balance are initialised.
We can write our own definition of a method that already exists in a base class. This is called method overriding. We have overridden the deposit( ) and withdraw( ) methods in the savingaccount class so that we can make sure that each account maintains a minimum balance of Rs. 500 and the total number of transactions do not exceed 10. From these methods we have called the base class's methods to update the balance using the base keyword. We have also overridden the display( ) method to display additional information, i.e. account number.
Working of currentaccount class is more or less similar to that of savingaccount class.
Using the derived class's object, if we call a method that is not overridden in the derived class, the base class method gets executed. Using derived class's object we can call base class's methods, but the reverse is not allowed.
Unlike C++, C# does not support multiple inheritance. So, in C# every class has exactly one base class.
Now, suppose we declare reference to the base class and store in it the address of instance of derived class as shown below.
account a1 = new savingaccount ( "Amar", 5600.00f ) ;
account a2 = new currentaccount ( "MyCompany Pvt. Ltd.", 126000.00f) ;
Such a situation arises when we have to decide at run-time a method of which class in a class hierarchy should get called. Using a1 and a2, suppose we call the method display( ), ideally the method of derived class should get called. But it is the method of base class that gets called. This is because the compiler considers the type of reference (account in this case) and resolves the method call. So, to call the proper method we must make a small change in our program. We must use the virtual keyword while defining the methods in base class as shown below.
public virtual void display( ) { }
We must declare the methods as virtual if they are going to be overridden in derived class. To override a virtual method in derived classes we must use the override keyword as given below.
public override void display( ) { }
Now it is ensured that when we call the methods using upcasted reference, it is the derived class's method that would get called. Actually, when we declare a virtual method, while calling it, the compiler considers the contents of the reference rather than its type.
If we don't want to override base class's virtual method, we can declare it with new modifier in derived class. The new modifier indicates that the method is new to this class and is not an override of a base class method.
Server side code executes on the server.For this to occur page has to be submitted or posted back.Events fired by the controls are executed on the server.Client side code executes in the browser of the client without submitting the page.
e.g. In ASP.NET for webcontrols like asp:button the click event of the button is executed on the server hence the event handler for the same in a part of the code-behind (server-side code). Along the server-side code events one can also attach client side events which are executed in the clients browser i.e. javascript events.
How does VB.NET/C# achieve polymorphism?
Polymorphism is also achieved through interfaces. Like abstract classes, interfaces also describe the methods that a class needs to implement. The difference between abstract classes and interfaces is that abstract classes always act as a base class of the related classes in the class hierarchy. For example, consider a hierarchy-car and truck classes derived from four-wheeler class; the classes two-wheeler and four-wheeler derived from an abstract class vehicle. So, the class 'vehicle' is the base class in the class hierarchy. On the other hand dissimilar classes can implement one interface. For example, there is an interface that compares two objects. This interface can be implemented by the classes like box, person and string, which are unrelated to each other.
C# allows multiple interface inheritance. It means that a class can implement more than one interface. The methods declared in an interface are implicitly abstract. If a class implements an interface, it becomes mandatory for the class to override all the methods declared in the interface, otherwise the derived class would become abstract.
Can you explain what inheritance is and an example of when you might use it?
The savingaccount class has two data members-accno that stores account number, and trans that keeps track of the number of transactions. We can create an object of savingaccount class as shown below.
savingaccount s = new savingaccount ( "Amar", 5600.00f ) ;
From the constructor of savingaccount class we have called the two-argument constructor of the account class using the base keyword and passed the name and balance to this constructor using which the data member's name and balance are initialised.
We can write our own definition of a method that already exists in a base class. This is called method overriding. We have overridden the deposit( ) and withdraw( ) methods in the savingaccount class so that we can make sure that each account maintains a minimum balance of Rs. 500 and the total number of transactions do not exceed 10. From these methods we have called the base class's methods to update the balance using the base keyword. We have also overridden the display( ) method to display additional information, i.e. account number.
Working of currentaccount class is more or less similar to that of savingaccount class.
Using the derived class's object, if we call a method that is not overridden in the derived class, the base class method gets executed. Using derived class's object we can call base class's methods, but the reverse is not allowed.
Unlike C++, C# does not support multiple inheritance. So, in C# every class has exactly one base class.
Now, suppose we declare reference to the base class and store in it the address of instance of derived class as shown below.
account a1 = new savingaccount ( "Amar", 5600.00f ) ;
account a2 = new currentaccount ( "MyCompany Pvt. Ltd.", 126000.00f) ;
Such a situation arises when we have to decide at run-time a method of which class in a class hierarchy should get called. Using a1 and a2, suppose we call the method display( ), ideally the method of derived class should get called. But it is the method of base class that gets called. This is because the compiler considers the type of reference (account in this case) and resolves the method call. So, to call the proper method we must make a small change in our program. We must use the virtual keyword while defining the methods in base class as shown below.
public virtual void display( ) { }
We must declare the methods as virtual if they are going to be overridden in derived class. To override a virtual method in derived classes we must use the override keyword as given below.
public override void display( ) { }
Now it is ensured that when we call the methods using upcasted reference, it is the derived class's method that would get called. Actually, when we declare a virtual method, while calling it, the compiler considers the contents of the reference rather than its type.
If we don't want to override base class's virtual method, we can declare it with new modifier in derived class. The new modifier indicates that the method is new to this class and is not an override of a base class method.
ASP.NET 2.0Interview Questions see
Which class can be used to perform data type conversion between .NET data types and XML types?
Which class can be used to create an XML document from scratch?
To perform asynchronous data access, what must be added to the connection string?
While developing ASP.NET 2.0 web application you have a DataSet containing a Customer DataTable and an Order DataTable. You want to easily navigate from an Order DataRow to the Customer who placed the order. What object will allow you to easily navigate from the Order to the Customer?
You are working with a DataSet and want to be able to display data, sorted different ways. How do you do so?
How will you identify which event in the ASP.NET Web page life cycle takes the longest time to execute?
What event can you subscribe to if you want to display information from SQL Print statements?
In the Design view in Visual Studio 2005 of an ASP.NET web page, what is the easiest way to create an event handler for the default event of a ASP.NET server control?
Which of the following is a requirement when merging modified data into a DataSet?
In your ASP.NET 2.0 web application you want to display an image that is selected from a collection of images. What approach will you use to implementing this?
Which of the following ways can you proactively clean up a database connection’s resources?
You are interested in examining the data that is posted to the Web server. What trace result section can you use to see this information?
You are writing ASP.NET 2.0 Web site that collects lots of data from users, and the data collection forms spreads over multiple ASP.NET Web pages. When the user reaches the last page, you need to gather all of data, validate the data, and save the data to the SQL Server database. You have noticed that it can be rather difficult to gather the data that is spread over multiple pages and you want to simplify this application. What is the easiest control to implement that can be used to collect the data on a single Web page?
For separating server-side code from client-side code on a ASP.NET page, what programming model should you use?
In your ASP.NET web application you want to display a list of clients on a Web page. The client list displays 10 clients at a time, and you require the ability to edit the clients. Which Web control is the best choice for this scenario?
Amit created a new Web site using Visual Studio 2005 in programming language C#. Later, Amit received an existing Web page from his boss, which consisted of the Contact.aspx file with the Contact.aspx.vb code-behind page. What must Amit do to use these files?
While creating web site you need to add an HTML Web server control to the Web page, you need to drag an HTML element from the ToolBox of Visual Studio 2005 to the Web page and then which of the following tasks you will perform?
For your ASP.NET web application your graphics designer created elaborate images that show the product lines of your company. Some of graphics of the product line are rectangular, circular, and others are having complex shapes. You need to use these images as a menu on your Web site. What is the best way of incorporating these images into your Web site?
What is the name of the property of ASP.NET page that you can query to determine that a ASP.NET page is being requested not data being submitted to web server?
While testing your ASP.NET web application you noticed that while clicking on CheckBox of one of the web page it does not cause a PostBack; you required that the CheckBox should make PostBack so Web page can be update on the server-side code. How can you make the CheckBox to cause a PostBack?
While creating an ASP.NET web application with the help of Visual Studio 2005 you are creates a Web page that has several related buttons, such as fast-forward, reverse, play, stop, and pause. There should be one event handler that handles the processes of PostBack from these Button server controls. Other than the normal Submit button, what type of button can you create?
Which of the following represents the best use of the Table, TableRow, and Table-Cell controls?
While developing ASP.NET 2.0 web application you want to display a list of parts in a master/detail scenario where the user can select a part number using a list that takes a minimum amount of space on the Web page. When the part is selected, a DetailsView control displays all the information about the part and allows the user to edit the part. Which Web control is the best choice to display the part number list for this scenario?
If you want to make a configuration setting change in your server that will affect to all Web and Windows applications on the current machine. Where you will make the changes?
For making a configuration setting change that will affect only the current Web application. Is there any tool that has a user-friendly Graphical User Interface (GUI)?
If you want to make a configuration setting change that will affect only the current Web application. Which file will you change?
While creating a Web site with the help of Visual Studio 2005 on a remote computer that does not have Front Page Server Extensions installed, which Web site type will you create in Visual Studio 2005?
While writing code in Visual Studio 2005 you creates a new instance of a ASP.NET TextBox server control, what do you need to do to get the TextBox to display on the Web page?
While creating your ASP.NET web based application you want to create multiple RadioButton server controls which should be mutually exclusive, what property of RadioButton server controls you must set?
Which class can be used to create an XML document from scratch?
To perform asynchronous data access, what must be added to the connection string?
While developing ASP.NET 2.0 web application you have a DataSet containing a Customer DataTable and an Order DataTable. You want to easily navigate from an Order DataRow to the Customer who placed the order. What object will allow you to easily navigate from the Order to the Customer?
You are working with a DataSet and want to be able to display data, sorted different ways. How do you do so?
How will you identify which event in the ASP.NET Web page life cycle takes the longest time to execute?
What event can you subscribe to if you want to display information from SQL Print statements?
In the Design view in Visual Studio 2005 of an ASP.NET web page, what is the easiest way to create an event handler for the default event of a ASP.NET server control?
Which of the following is a requirement when merging modified data into a DataSet?
In your ASP.NET 2.0 web application you want to display an image that is selected from a collection of images. What approach will you use to implementing this?
Which of the following ways can you proactively clean up a database connection’s resources?
You are interested in examining the data that is posted to the Web server. What trace result section can you use to see this information?
You are writing ASP.NET 2.0 Web site that collects lots of data from users, and the data collection forms spreads over multiple ASP.NET Web pages. When the user reaches the last page, you need to gather all of data, validate the data, and save the data to the SQL Server database. You have noticed that it can be rather difficult to gather the data that is spread over multiple pages and you want to simplify this application. What is the easiest control to implement that can be used to collect the data on a single Web page?
For separating server-side code from client-side code on a ASP.NET page, what programming model should you use?
In your ASP.NET web application you want to display a list of clients on a Web page. The client list displays 10 clients at a time, and you require the ability to edit the clients. Which Web control is the best choice for this scenario?
Amit created a new Web site using Visual Studio 2005 in programming language C#. Later, Amit received an existing Web page from his boss, which consisted of the Contact.aspx file with the Contact.aspx.vb code-behind page. What must Amit do to use these files?
While creating web site you need to add an HTML Web server control to the Web page, you need to drag an HTML element from the ToolBox of Visual Studio 2005 to the Web page and then which of the following tasks you will perform?
For your ASP.NET web application your graphics designer created elaborate images that show the product lines of your company. Some of graphics of the product line are rectangular, circular, and others are having complex shapes. You need to use these images as a menu on your Web site. What is the best way of incorporating these images into your Web site?
What is the name of the property of ASP.NET page that you can query to determine that a ASP.NET page is being requested not data being submitted to web server?
While testing your ASP.NET web application you noticed that while clicking on CheckBox of one of the web page it does not cause a PostBack; you required that the CheckBox should make PostBack so Web page can be update on the server-side code. How can you make the CheckBox to cause a PostBack?
While creating an ASP.NET web application with the help of Visual Studio 2005 you are creates a Web page that has several related buttons, such as fast-forward, reverse, play, stop, and pause. There should be one event handler that handles the processes of PostBack from these Button server controls. Other than the normal Submit button, what type of button can you create?
Which of the following represents the best use of the Table, TableRow, and Table-Cell controls?
While developing ASP.NET 2.0 web application you want to display a list of parts in a master/detail scenario where the user can select a part number using a list that takes a minimum amount of space on the Web page. When the part is selected, a DetailsView control displays all the information about the part and allows the user to edit the part. Which Web control is the best choice to display the part number list for this scenario?
If you want to make a configuration setting change in your server that will affect to all Web and Windows applications on the current machine. Where you will make the changes?
For making a configuration setting change that will affect only the current Web application. Is there any tool that has a user-friendly Graphical User Interface (GUI)?
If you want to make a configuration setting change that will affect only the current Web application. Which file will you change?
While creating a Web site with the help of Visual Studio 2005 on a remote computer that does not have Front Page Server Extensions installed, which Web site type will you create in Visual Studio 2005?
While writing code in Visual Studio 2005 you creates a new instance of a ASP.NET TextBox server control, what do you need to do to get the TextBox to display on the Web page?
While creating your ASP.NET web based application you want to create multiple RadioButton server controls which should be mutually exclusive, what property of RadioButton server controls you must set?
Tough ASP.NET interview questions all see
1. Describe the difference between a Thread and a Process?
2. What is a Windows Service and how does its lifecycle differ from a “standard” EXE?
3. What is the maximum amount of memory any single process on Windows can address? Is this different than the maximum virtual memory for the system? How would this affect a system design?
4. What is the difference between an EXE and a DLL?
5. What is strong-typing versus weak-typing? Which is preferred? Why?
6. What’s wrong with a line like this? DateTime.Parse(myString
7. What are PDBs? Where must they be located for debugging to work?
8. What is cyclomatic complexity and why is it important?
9. Write a standard lock() plus double check to create a critical section around a variable access.
10. What is FullTrust? Do GAC’ed assemblies have FullTrust?
11. What benefit does your code receive if you decorate it with attributes demanding specific Security permissions?
12. What does this do? gacutil /l | find /i “about”
13. What does this do? sn -t foo.dll
14. What ports must be open for DCOM over a firewall? What is the purpose of Port 135?
15. Contrast OOP and SOA. What are tenets of each
16. How does the XmlSerializer work? What ACL permissions does a process using it require?
17. Why is catch(Exception) almost always a bad idea?
18. What is the difference between Debug.Write and Trace.Write? When should each be used?
19. What is the difference between a Debug and Release build? Is there a significant speed difference? Why or why not?
20. Does JITting occur per-assembly or per-method? How does this affect the working set?
21. Contrast the use of an abstract base class against an interface?
22. What is the difference between a.Equals(b) and a == b?
23. In the context of a comparison, what is object identity versus object equivalence?
24. How would one do a deep copy in .NET?
25. Explain current thinking around IClonable.
26. What is boxing?
27. Is string a value type or a reference type?
2. What is a Windows Service and how does its lifecycle differ from a “standard” EXE?
3. What is the maximum amount of memory any single process on Windows can address? Is this different than the maximum virtual memory for the system? How would this affect a system design?
4. What is the difference between an EXE and a DLL?
5. What is strong-typing versus weak-typing? Which is preferred? Why?
6. What’s wrong with a line like this? DateTime.Parse(myString
7. What are PDBs? Where must they be located for debugging to work?
8. What is cyclomatic complexity and why is it important?
9. Write a standard lock() plus double check to create a critical section around a variable access.
10. What is FullTrust? Do GAC’ed assemblies have FullTrust?
11. What benefit does your code receive if you decorate it with attributes demanding specific Security permissions?
12. What does this do? gacutil /l | find /i “about”
13. What does this do? sn -t foo.dll
14. What ports must be open for DCOM over a firewall? What is the purpose of Port 135?
15. Contrast OOP and SOA. What are tenets of each
16. How does the XmlSerializer work? What ACL permissions does a process using it require?
17. Why is catch(Exception) almost always a bad idea?
18. What is the difference between Debug.Write and Trace.Write? When should each be used?
19. What is the difference between a Debug and Release build? Is there a significant speed difference? Why or why not?
20. Does JITting occur per-assembly or per-method? How does this affect the working set?
21. Contrast the use of an abstract base class against an interface?
22. What is the difference between a.Equals(b) and a == b?
23. In the context of a comparison, what is object identity versus object equivalence?
24. How would one do a deep copy in .NET?
25. Explain current thinking around IClonable.
26. What is boxing?
27. Is string a value type or a reference type?
ASP.NET INTERVIEW QUESTIONS 16
Question:-What do you mean by Share Point Portal ?
Answer: Here I have taken information regarding Share Point Portal Server 2003 provides mainly access to the crucial business information and applications.With the help of Share Point Server we can server information between Public Folders, Data Bases, File Servers and the websites that are based on Windows server 2003. This Share Point Portal is integrated with MSAccess and Windows servers,So we can get a Wide range of document management functionality. We can also create a full featured portal with readymade navigation and structure.
Question:-What is cross page posting in ASP.NET2.0 ?
Answer: When we have to post data from one page to another in application we used server.transfer method but in this the URL remains the same but in cross page posting there is little different there is normal post back is done but in target page we can access values of server control in the source page.This is quite simple we have to only set the PostBackUrl property of Button,LinkButton or imagebutton which specifies the target page.In target page we can access the PreviousPage property.And we have to use the @PreviousPageType directive.We can access control of PreviousPage by using the findcontrol method.When we set the PostBackURL property ASP.NET framework bind the HTML and Javascript function automatically.
Question: What you thing about the WebPortal ?
Answer: Web portal is nothing but a page that allows a user to customize his/her homepage. We can use Widgets to create that portal we have only to drag and drop widgets on the page. The user can set his Widgets on any where on the page where he has to get them. Widgets are nothing but a page area that helps particular function to response. Widgets example are address books, contact lists, RSS feeds, clocks, calendars, play lists, stock tickers, weather reports, traffic reports, dictionaries, games and another such beautiful things that we can not imagine. We can also say Web Parts in Share Point Portal. These are one of Ajax-Powered.
Question: How to start Outlook,NotePad file in AsP.NET with code ?
Answer: Here is the syntax to open outlook or notepad file in ASP.NET VB.NET Process.Start("Notepad.exe") Process.Start("msimn.exe"); C#.NET System.Diagnostics.Process.Start("msimn.exe"); System.Diagnostics.Process.Start("Notepad.exe");
Question: What is the purpose of IIS ?
Answer: We can call IIS(Internet Information Services) a powerful Web server that helps us creating highly reliable, scalable and manageable infrastructure for Web application which runs on Windows Server 2003. IIS helps development center and increase Web site and application availability while lowering system administration costs. It also runs on Windows NT/2000 platforms and also for above versions. With IIS, Microsoft includes a set of programs for building and administering Web sites, a search engine, and support for writing Web-based applications that access database. IIS also called http server since it process the http request and gets http response.
Question: What is main difference between GridLayout and FormLayout ?
Answer: GridLayout helps in providing absolute positioning of every control placed on the page.It is easier to devlop page with absolute positioning because control can be placed any where according to our requirement.But FormLayout is little different only experience Web Devloper used this one reason is it is helpful for wider range browser.If there is absolute positioning we can notice that there are number of DIV tags.But in FormLayout whole work are done through the tables.
Question: How Visual SourceSafe helps Us ?
Answer: One of the powerful tool provided by Microsoft to keep up-to-date of files system its keeps records of file history once we add files to source safe it can be add to database and the changes ade by diffrenet user to this files are maintained in database from that we can get the older version of files to.This also helps in sharing,merging of files.
Question:-Can you define what is SharePoint and some overview about this ?
Answer: SharePoint helps workers for creating powerful personalized interfaces only by dragging and drop pre-defined Web Part Components. And these Web Parts components also helps non programmers to get information which care and customize the appearance of Web pages. To under stand it we take an example one Web Part might display a user's information another might create a graph showing current employee status and a third might show a list of Employees Salary. This is also possible that each functions has a link to a video or audio presentation.So now Developers are unable to create these Web Part components and make them available to SharePoint users.
Question:-What is different between WebUserControl and in WebCustomControl ?
Answer: Web user controls :- Web User Control is Easier to create and another thing is that its support is limited for users who use a visual design tool one gud thing is that its contains static layout one more thing a seprate copy is required for each application.
Web custom controls:-Web Custom Control is typical to create and gud for dynamic layout and another thing is it have full tool support for user and a single copy of control is required because it is placed in Global Assembly cache.
Question:-What is Sandbox in SQL server and explain permission level in Sql Server ?
Answer: Sandbox is place where we run trused program or script which is created from the third party. There are three type of Sandbox where user code run.
Safe Access Sandbox:-Here we can only create stored procedure,triggers,functions,datatypes etc.But we doesnot have acess memory ,disk etc.
External Access Sandbox:-We cn access File systems outside the box. We can not play with threading,memory allocation etc.
Unsafe Access Sandbox:-Here we can write unreliable and unsafe code.
Question:-How many types of cookies are there in .NET ?
Answer: Two type of cookeies.
a) single valued eg request.cookies(”UserName”).value=”dotnetquestion”
b)Multivalued cookies. These are used in the way collections are used example
request.cookies(”CookiName”)(”UserName”)=”dotnetquestionMahesh”
request.cookies(”CookiName”)(”UserID”)=”interview″
Question: When we get Error 'HTTP 502 Proxy Error' ?
Answer: We get this error when we execute ASP.NET Web pages in Visual Web Developer Web server, because the URL randomly select port number and proxy servers did not recognize the URL and return this error. To resolve this problem we have to change settings in Internet Explorer to bypass the proxy server for local addresses, so that the request is not sent to the proxy.
Question:-What do you mean by three-tier architecture?
Answer: The three-tier architecture was comes into existence to improve management of code and contents and to improve the performance of the web based applications.There are mainly three layers in three-tier architecture.the are define as follows
(1)Presentation
(2)Business Logic
(3)Database
(1)First layer Presentation contains mainly the interface code, and this is shown to user. This code could contain any technology that can be used on the client side like HTML, JavaScript or VBScript etc.
(2)Second layer is Business Logic which contains all the code of the server-side .This layer have code to interact with database database and to query, manipulate, pass data to user interface and handle any input from the UI as well.
(3)Third layer Data represents the data store like MS Access, SQL Server, an XML file, an Excel file or even a text file containing data also some addtional database are also added to that layers.
Question: What is Finalizer in .NET define Dispose and Finalize ?
Answer: We can say that Finalizer are the methods that's helps in cleanp the code that is executed before object is garbage collected .The process is called finalization . There are two methods of finalizer Dispose and Finalize .There is little diffrenet between two of this method .
When we call Dispose method is realse all the resources hold by an object as well as all the resorces hold by the parent object.When we call Dispose method it clean managed as well as unmanaged resources.
Finalize methd also cleans resources but finalize call dispose clears only the unmanged resources because in finalization the garbase collecter clears all the object hold by managed code so finalization fails to prevent thos one of methd is used that is: GC.SuppressFinalize.
Question: Define SMTPclient class in DotNet framework class libarary ?
Answer: Each classes in dotnet framework inclue some properties,method and events.These properties ,methods and events are member of a class.SMTPclient class mainly concern with sending mail.This class contain the folling member.
Properties:-
Host:-The name or IP address of email server.
Port:-Port that is use when sending mail.
Methods:-
Send:-Enables us to send email synchronously.
SendAsynchronous:-Enables us to send an email asynchronously.
Event:-
SendCompleted:-This event raised when an asynchronous send opertion completes.
Question: What is late binding ?
Answer: When code interacts with an object dynamically at runtime .because our code literally doesnot care what type of object it is interacting and with the methods thats are supported by object and with the methods thats are supported by object .The type of object is not known by the IDE or compiler ,no Intellisense nor compile-time syntax checking is possible but we get unprecedented flexibilty in exchange.if we enable strict type checking by using option strict on at the top of our code modules ,then IDE and compiler will enforce early binding behaviour .By default Late binding is done.
Question:-Does .NET CLR and SQL SERVER run in different process ?
Answer: Dot Net CLR and all .net realtes application and Sql Server run in same process or we can say that that on the same address because there is no issue of speed because if these two process are run in different process then there may be a speed issue created one process goes fast and other slow may create the problem.
Question:-What is Com Marshler and its importance in .NET ?
Answer: Com Marshler is one of useful component of CLR. Its Task is to marshal data between Managed and Unmanaged environment .It helps in representation of data accross diffrenet execution enviroment.It performs the conversion of data format between manage and unmanaged code.By the helps of Com Marshlar CLR allows manage code to interoperate with unmanaged code.
Question: What is CSU and its description ?
Answer: CSU stands for comma separate values also called comma delimited.It is plain text file which stores spreadsheets or basic datatype in very simple format.One record in each line and each field separted with comma's it is often used to transfer large ammount spreadsheet data or database information between program.
Question: The IHttpHandler and IHttpHandlerFactory interfaces ?
Answer: The IHttpHandler interface is implemented by all the handlers. The interface consists of one property called IsReusable. The IsReusable property gets a value indicating whether another request can use the IHttpHandler instance. The method ProcessRequest() allows you to process the current request. This is the core place where all your code goes. This method receives a parameter of type HttpContext using which you can access the intrinsic objects such as Request and Response. The IHttpHandlerFactory interface consists of two methods - GetHandler and ReleaseHandler. The GetHandler() method instantiates the required HTTP handler based on some condition and returns it back to ASP.NET. The ReleaseHandler() method allows the factory to reuse an existing handler.
Question: what is Viewstate?
Answer:View state is used by the ASP.NET page framework to automatically save the values of the page and of each control just prior to rendering to the page. When the page is posted, one of the first tasks performed by page processing is to restore view state.
State management is the process by which you maintain state and page information over multiple requests for the same or different pages.
Client-side options are:
* The ViewState property * Query strings
* Hidden fields * Cookies
Server-side options are:
* Application state * Session state * DataBase
Use the View State property to save data in a hidden field on a page. Because ViewState stores data on the page, it is limited to items that can be serialized. If you want to store more complex items in View State, you must convert the items to and from a string.
ASP.NET provides the following ways to retain variables between requests:
Context.Handler object Use this object to retrieve public members of one Web form’s class from a subsequently displayed Web form.
Query strings Use these strings to pass information between requests and responses as part of the Web address. Query strings are visible to the user, so they should not contain secure information such as passwords.
Cookies Use cookies to store small amounts of information on a client. Clients might refuse cookies, so your code has to anticipate that possibility.
View state ASP.NET stores items added to a page’s ViewState property as hidden fields on the page.
Session state Use Session state variables to store items that you want keep local to the current session (single user).
Application state Use Application state variables to store items that you want be available to all users of the application.
Question: DOTNET PAGE LIFECYCLE ?
Answer: While excuting the page, it will go under the fallowing steps(or fires the events) which collectivly known as Page Life cycle.
Page_Init -- Page Initialization
LoadViewState -- View State Loading
LoadPostData -- Postback data processing
Page_Load -- Page Loading
RaisePostDataChangedEvent -- PostBack Change Notification
RaisePostBackEvent -- PostBack Event Handling
Page_PreRender -- Page Pre Rendering Phase
SaveViewState -- View State Saving
Page_Render -- Page Rendering
Page_UnLoad -- Page Unloading
Question: What is Satellite Assemblies ?
Answer: Satellite assemblies are often used to deploy language-specific resources for an application. These language-specific assemblies work in side-by-side execution because the application has a separate product ID for each language and installs satellite assemblies in a language-specific subdirectory for each language. When uninstalling, the application removes only the satellite assemblies associated with a given language and .NET Framework version. No core .NET Framework files are removed unless the last language for that .NET Framework version is being removed. For example, English and Japanese editions of the .NET Framework version 1.1 share the same core files. The Japanese .NET Framework version 1.1 adds satellite assemblies with localized resources in a \ja subdirectory. An application that supports the .NET Framework version 1.1, regardless of its language, always uses the same core runtime files.
Question: What is CAS ?
Answer:CAS: CAS is the part of the .NET security model that determines whether or not a piece of code is allowed to run, and what resources it can use when it is running. For example, it is CAS that will prevent a .NET web applet from formatting your hard disk. How does CAS work? The CAS security policy revolves around two key concepts - code groups and permissions. Each .NET assembly is a member of a particular code group, and each code group is granted the permissions specified in a named permission set. For example, using the default security policy, a control downloaded from a web site belongs to the 'Zone - Internet' code group, which adheres to the permissions defined by the 'Internet' named permission set. (Naturally the 'Internet' named permission set represents a very restrictive range of permissions.)
Question: Automatic Memory Management ?
Answer: Automatic Memory Management: From a programmer's perspective, this is probably the single biggest benefit of the .NET Framework. No, I'm not kidding. Every project I've worked on in my long career of DOS and Windows development has suffered at some point from memory management issues. Proper memory management is hard. Even very good programmers have difficulty with it. It's entirely too easy for a small mistake to cause a program to chew up memory and crash, sometimes bringing the operating system to a screeching halt in the process.
Programmers understand that they're responsible for releasing any memory that they allocate, but they're not very good at actually doing it. In addition, functions that allocate memory as a side effect abound in the Windows API and in the C runtime library. It's nearly impossible for a programmer to know all of the rules. Even when the programmer follows the rules, a small memory leak in a support library can cause big problems if called enough.
The .NET Framework solves the memory management problems by implementing a garbage collector that can keep track of allocated memory references and release the memory when it is no longer referenced. A large part of what makes this possible is the blazing speed of today's processors. When you're running a 2 GHz machine, it's easy to spare a few cycles for memory management. Not that the garbage collector takes a huge number of cycles--it's incredibly efficient.
The garbage collector isn't perfect and it doesn't solve the problem of mis-managing other scarce resources (file handles, for example), but it relieves programmers from having to worry about a huge source of bugs that trips almost everybody up in other programming environments.
On balance, automatic memory management is a huge win in almost every situation.
Question: What Language familar to CLR?
Answer: Any language that can be compiled into Microsoft Intermediate Language (MSIL) is considered a .NET-compliant language. Following are a few of the popular .NET-compliant languages supported by CLR:
APL COBOL Component Pascal Eiffel
Fortran Haskell JScript Mercury
Oberon Pascal Perl Python
Smalltalk Visual Basic Visual C# Visual C++
Answer: Here I have taken information regarding Share Point Portal Server 2003 provides mainly access to the crucial business information and applications.With the help of Share Point Server we can server information between Public Folders, Data Bases, File Servers and the websites that are based on Windows server 2003. This Share Point Portal is integrated with MSAccess and Windows servers,So we can get a Wide range of document management functionality. We can also create a full featured portal with readymade navigation and structure.
Question:-What is cross page posting in ASP.NET2.0 ?
Answer: When we have to post data from one page to another in application we used server.transfer method but in this the URL remains the same but in cross page posting there is little different there is normal post back is done but in target page we can access values of server control in the source page.This is quite simple we have to only set the PostBackUrl property of Button,LinkButton or imagebutton which specifies the target page.In target page we can access the PreviousPage property.And we have to use the @PreviousPageType directive.We can access control of PreviousPage by using the findcontrol method.When we set the PostBackURL property ASP.NET framework bind the HTML and Javascript function automatically.
Question: What you thing about the WebPortal ?
Answer: Web portal is nothing but a page that allows a user to customize his/her homepage. We can use Widgets to create that portal we have only to drag and drop widgets on the page. The user can set his Widgets on any where on the page where he has to get them. Widgets are nothing but a page area that helps particular function to response. Widgets example are address books, contact lists, RSS feeds, clocks, calendars, play lists, stock tickers, weather reports, traffic reports, dictionaries, games and another such beautiful things that we can not imagine. We can also say Web Parts in Share Point Portal. These are one of Ajax-Powered.
Question: How to start Outlook,NotePad file in AsP.NET with code ?
Answer: Here is the syntax to open outlook or notepad file in ASP.NET VB.NET Process.Start("Notepad.exe") Process.Start("msimn.exe"); C#.NET System.Diagnostics.Process.Start("msimn.exe"); System.Diagnostics.Process.Start("Notepad.exe");
Question: What is the purpose of IIS ?
Answer: We can call IIS(Internet Information Services) a powerful Web server that helps us creating highly reliable, scalable and manageable infrastructure for Web application which runs on Windows Server 2003. IIS helps development center and increase Web site and application availability while lowering system administration costs. It also runs on Windows NT/2000 platforms and also for above versions. With IIS, Microsoft includes a set of programs for building and administering Web sites, a search engine, and support for writing Web-based applications that access database. IIS also called http server since it process the http request and gets http response.
Question: What is main difference between GridLayout and FormLayout ?
Answer: GridLayout helps in providing absolute positioning of every control placed on the page.It is easier to devlop page with absolute positioning because control can be placed any where according to our requirement.But FormLayout is little different only experience Web Devloper used this one reason is it is helpful for wider range browser.If there is absolute positioning we can notice that there are number of DIV tags.But in FormLayout whole work are done through the tables.
Question: How Visual SourceSafe helps Us ?
Answer: One of the powerful tool provided by Microsoft to keep up-to-date of files system its keeps records of file history once we add files to source safe it can be add to database and the changes ade by diffrenet user to this files are maintained in database from that we can get the older version of files to.This also helps in sharing,merging of files.
Question:-Can you define what is SharePoint and some overview about this ?
Answer: SharePoint helps workers for creating powerful personalized interfaces only by dragging and drop pre-defined Web Part Components. And these Web Parts components also helps non programmers to get information which care and customize the appearance of Web pages. To under stand it we take an example one Web Part might display a user's information another might create a graph showing current employee status and a third might show a list of Employees Salary. This is also possible that each functions has a link to a video or audio presentation.So now Developers are unable to create these Web Part components and make them available to SharePoint users.
Question:-What is different between WebUserControl and in WebCustomControl ?
Answer: Web user controls :- Web User Control is Easier to create and another thing is that its support is limited for users who use a visual design tool one gud thing is that its contains static layout one more thing a seprate copy is required for each application.
Web custom controls:-Web Custom Control is typical to create and gud for dynamic layout and another thing is it have full tool support for user and a single copy of control is required because it is placed in Global Assembly cache.
Question:-What is Sandbox in SQL server and explain permission level in Sql Server ?
Answer: Sandbox is place where we run trused program or script which is created from the third party. There are three type of Sandbox where user code run.
Safe Access Sandbox:-Here we can only create stored procedure,triggers,functions,datatypes etc.But we doesnot have acess memory ,disk etc.
External Access Sandbox:-We cn access File systems outside the box. We can not play with threading,memory allocation etc.
Unsafe Access Sandbox:-Here we can write unreliable and unsafe code.
Question:-How many types of cookies are there in .NET ?
Answer: Two type of cookeies.
a) single valued eg request.cookies(”UserName”).value=”dotnetquestion”
b)Multivalued cookies. These are used in the way collections are used example
request.cookies(”CookiName”)(”UserName”)=”dotnetquestionMahesh”
request.cookies(”CookiName”)(”UserID”)=”interview″
Question: When we get Error 'HTTP 502 Proxy Error' ?
Answer: We get this error when we execute ASP.NET Web pages in Visual Web Developer Web server, because the URL randomly select port number and proxy servers did not recognize the URL and return this error. To resolve this problem we have to change settings in Internet Explorer to bypass the proxy server for local addresses, so that the request is not sent to the proxy.
Question:-What do you mean by three-tier architecture?
Answer: The three-tier architecture was comes into existence to improve management of code and contents and to improve the performance of the web based applications.There are mainly three layers in three-tier architecture.the are define as follows
(1)Presentation
(2)Business Logic
(3)Database
(1)First layer Presentation contains mainly the interface code, and this is shown to user. This code could contain any technology that can be used on the client side like HTML, JavaScript or VBScript etc.
(2)Second layer is Business Logic which contains all the code of the server-side .This layer have code to interact with database database and to query, manipulate, pass data to user interface and handle any input from the UI as well.
(3)Third layer Data represents the data store like MS Access, SQL Server, an XML file, an Excel file or even a text file containing data also some addtional database are also added to that layers.
Question: What is Finalizer in .NET define Dispose and Finalize ?
Answer: We can say that Finalizer are the methods that's helps in cleanp the code that is executed before object is garbage collected .The process is called finalization . There are two methods of finalizer Dispose and Finalize .There is little diffrenet between two of this method .
When we call Dispose method is realse all the resources hold by an object as well as all the resorces hold by the parent object.When we call Dispose method it clean managed as well as unmanaged resources.
Finalize methd also cleans resources but finalize call dispose clears only the unmanged resources because in finalization the garbase collecter clears all the object hold by managed code so finalization fails to prevent thos one of methd is used that is: GC.SuppressFinalize.
Question: Define SMTPclient class in DotNet framework class libarary ?
Answer: Each classes in dotnet framework inclue some properties,method and events.These properties ,methods and events are member of a class.SMTPclient class mainly concern with sending mail.This class contain the folling member.
Properties:-
Host:-The name or IP address of email server.
Port:-Port that is use when sending mail.
Methods:-
Send:-Enables us to send email synchronously.
SendAsynchronous:-Enables us to send an email asynchronously.
Event:-
SendCompleted:-This event raised when an asynchronous send opertion completes.
Question: What is late binding ?
Answer: When code interacts with an object dynamically at runtime .because our code literally doesnot care what type of object it is interacting and with the methods thats are supported by object and with the methods thats are supported by object .The type of object is not known by the IDE or compiler ,no Intellisense nor compile-time syntax checking is possible but we get unprecedented flexibilty in exchange.if we enable strict type checking by using option strict on at the top of our code modules ,then IDE and compiler will enforce early binding behaviour .By default Late binding is done.
Question:-Does .NET CLR and SQL SERVER run in different process ?
Answer: Dot Net CLR and all .net realtes application and Sql Server run in same process or we can say that that on the same address because there is no issue of speed because if these two process are run in different process then there may be a speed issue created one process goes fast and other slow may create the problem.
Question:-What is Com Marshler and its importance in .NET ?
Answer: Com Marshler is one of useful component of CLR. Its Task is to marshal data between Managed and Unmanaged environment .It helps in representation of data accross diffrenet execution enviroment.It performs the conversion of data format between manage and unmanaged code.By the helps of Com Marshlar CLR allows manage code to interoperate with unmanaged code.
Question: What is CSU and its description ?
Answer: CSU stands for comma separate values also called comma delimited.It is plain text file which stores spreadsheets or basic datatype in very simple format.One record in each line and each field separted with comma's it is often used to transfer large ammount spreadsheet data or database information between program.
Question: The IHttpHandler and IHttpHandlerFactory interfaces ?
Answer: The IHttpHandler interface is implemented by all the handlers. The interface consists of one property called IsReusable. The IsReusable property gets a value indicating whether another request can use the IHttpHandler instance. The method ProcessRequest() allows you to process the current request. This is the core place where all your code goes. This method receives a parameter of type HttpContext using which you can access the intrinsic objects such as Request and Response. The IHttpHandlerFactory interface consists of two methods - GetHandler and ReleaseHandler. The GetHandler() method instantiates the required HTTP handler based on some condition and returns it back to ASP.NET. The ReleaseHandler() method allows the factory to reuse an existing handler.
Question: what is Viewstate?
Answer:View state is used by the ASP.NET page framework to automatically save the values of the page and of each control just prior to rendering to the page. When the page is posted, one of the first tasks performed by page processing is to restore view state.
State management is the process by which you maintain state and page information over multiple requests for the same or different pages.
Client-side options are:
* The ViewState property * Query strings
* Hidden fields * Cookies
Server-side options are:
* Application state * Session state * DataBase
Use the View State property to save data in a hidden field on a page. Because ViewState stores data on the page, it is limited to items that can be serialized. If you want to store more complex items in View State, you must convert the items to and from a string.
ASP.NET provides the following ways to retain variables between requests:
Context.Handler object Use this object to retrieve public members of one Web form’s class from a subsequently displayed Web form.
Query strings Use these strings to pass information between requests and responses as part of the Web address. Query strings are visible to the user, so they should not contain secure information such as passwords.
Cookies Use cookies to store small amounts of information on a client. Clients might refuse cookies, so your code has to anticipate that possibility.
View state ASP.NET stores items added to a page’s ViewState property as hidden fields on the page.
Session state Use Session state variables to store items that you want keep local to the current session (single user).
Application state Use Application state variables to store items that you want be available to all users of the application.
Question: DOTNET PAGE LIFECYCLE ?
Answer: While excuting the page, it will go under the fallowing steps(or fires the events) which collectivly known as Page Life cycle.
Page_Init -- Page Initialization
LoadViewState -- View State Loading
LoadPostData -- Postback data processing
Page_Load -- Page Loading
RaisePostDataChangedEvent -- PostBack Change Notification
RaisePostBackEvent -- PostBack Event Handling
Page_PreRender -- Page Pre Rendering Phase
SaveViewState -- View State Saving
Page_Render -- Page Rendering
Page_UnLoad -- Page Unloading
Question: What is Satellite Assemblies ?
Answer: Satellite assemblies are often used to deploy language-specific resources for an application. These language-specific assemblies work in side-by-side execution because the application has a separate product ID for each language and installs satellite assemblies in a language-specific subdirectory for each language. When uninstalling, the application removes only the satellite assemblies associated with a given language and .NET Framework version. No core .NET Framework files are removed unless the last language for that .NET Framework version is being removed. For example, English and Japanese editions of the .NET Framework version 1.1 share the same core files. The Japanese .NET Framework version 1.1 adds satellite assemblies with localized resources in a \ja subdirectory. An application that supports the .NET Framework version 1.1, regardless of its language, always uses the same core runtime files.
Question: What is CAS ?
Answer:CAS: CAS is the part of the .NET security model that determines whether or not a piece of code is allowed to run, and what resources it can use when it is running. For example, it is CAS that will prevent a .NET web applet from formatting your hard disk. How does CAS work? The CAS security policy revolves around two key concepts - code groups and permissions. Each .NET assembly is a member of a particular code group, and each code group is granted the permissions specified in a named permission set. For example, using the default security policy, a control downloaded from a web site belongs to the 'Zone - Internet' code group, which adheres to the permissions defined by the 'Internet' named permission set. (Naturally the 'Internet' named permission set represents a very restrictive range of permissions.)
Question: Automatic Memory Management ?
Answer: Automatic Memory Management: From a programmer's perspective, this is probably the single biggest benefit of the .NET Framework. No, I'm not kidding. Every project I've worked on in my long career of DOS and Windows development has suffered at some point from memory management issues. Proper memory management is hard. Even very good programmers have difficulty with it. It's entirely too easy for a small mistake to cause a program to chew up memory and crash, sometimes bringing the operating system to a screeching halt in the process.
Programmers understand that they're responsible for releasing any memory that they allocate, but they're not very good at actually doing it. In addition, functions that allocate memory as a side effect abound in the Windows API and in the C runtime library. It's nearly impossible for a programmer to know all of the rules. Even when the programmer follows the rules, a small memory leak in a support library can cause big problems if called enough.
The .NET Framework solves the memory management problems by implementing a garbage collector that can keep track of allocated memory references and release the memory when it is no longer referenced. A large part of what makes this possible is the blazing speed of today's processors. When you're running a 2 GHz machine, it's easy to spare a few cycles for memory management. Not that the garbage collector takes a huge number of cycles--it's incredibly efficient.
The garbage collector isn't perfect and it doesn't solve the problem of mis-managing other scarce resources (file handles, for example), but it relieves programmers from having to worry about a huge source of bugs that trips almost everybody up in other programming environments.
On balance, automatic memory management is a huge win in almost every situation.
Question: What Language familar to CLR?
Answer: Any language that can be compiled into Microsoft Intermediate Language (MSIL) is considered a .NET-compliant language. Following are a few of the popular .NET-compliant languages supported by CLR:
APL COBOL Component Pascal Eiffel
Fortran Haskell JScript Mercury
Oberon Pascal Perl Python
Smalltalk Visual Basic Visual C# Visual C++
dot see it
What is the .NET Framework?
The Microsoft .NET Framework is a platform for building, deploying, and running Web Services and applications. It provides a highly productive, standards-based, multi-language environment for integrating existing investments with next-generation applications and services as well as the agility to solve the challenges of deployment and operation of Internet-scale applications. The .NET Framework consists of three main parts: the common language runtime, a hierarchical set of unified class libraries, and a componentized version of Active Server Pages called
ASP.NET.
How many languages .NET is supporting now?
When .NET was introduced it came with several languages. VB.NET, C#, COBOL and Perl, etc. The site DotNetLanguages.Net says 44 languages are supported.
How is .NET able to support multiple languages?
.Net is a language should comply with the Common Language Runtime standard to become a .NET language. In .NET, code is compiled to Microsoft Intermediate Language (MSIL for short). This is called as Managed Code. This Managed code is run in .NET environment. So after compilation to this IL the language is not a barrier. A code can call or use a function written in another language.
Runtime Technical Questions
Terminology
What is the common language runtime (CLR)?
The common language runtime is the execution engine for .NET Framework applications.
It provides a number of services, including the following:
Code management (loading and execution)
Application memory isolation
Verification of type safety
Conversion of IL to native code
Access to metadata (enhanced type information)
Managing memory for managed objects
Enforcement of code access security
Exception handling, including cross-language exceptions
Interoperation between managed code, COM objects, and pre-existing DLLs (unmanaged code
and data)
Automation of object layout
Support for developer services (profiling, debugging, and so on)
What is the common type system (CTS)?
The common type system is a rich type system, built into the common language runtime, that supports the types and operations found in most programming languages. The common type system supports the complete implementation of a wide range of programming languages.
What is the Common Language Specification (CLS)?
The Common Language Specification is a set of constructs and constraints that serves as a guide for library writers and compiler writers. It allows libraries to be fully usable from any language supporting the CLS, and for those languages to integrate with each other. The Common Language Specification is a subset of the common type system. The Common Language Specification is also important to application developers who are writing code that will be used by other developers. When developers design publicly accessible APIs following the rules of the CLS, those APIs are easily used from all other programming languages that target the common language runtime.
What is the Microsoft Intermediate Language (MSIL)?
MSIL is the CPU-independent instruction set into which .NET Framework programs are compiled. It contains instructions for loading, storing, initializing, and calling methods on objects. Combined with metadata and the common type system, MSIL allows for true cross-language integration. Prior to execution, MSIL is converted to machine code. It is not interpreted.
What is managed code and managed data?
Managed code is code that is written to target the services of the common language runtime (see What is the Common Language Runtime?). In order to target these services, the code must provide a minimum level of information (metadata) to the runtime. All C#, Visual Basic .NET, and JScript .NET code is managed by default. Visual Studio .NET C++ code is not managed by default, but the compiler can produce managed code by specifying a command-line switch (/CLR). Closely related to managed code is managed data--data that is allocated and de-allocated by the common language runtime's garbage collector. C#, Visual Basic, and JScript .NET data is
managed by default. C# data can, however, be marked as unmanaged through the use of special keywords. Visual Studio .NET C++ data is unmanaged by default (even when using the /CLR switch), but when using Managed Extensions for C++, a class can be marked as managed by using the __gc keyword. As the name suggests, this means that the memory for instances of the class is managed by the garbage collector. In addition, the class becomes a full participating member of the .NET Framework community, with the benefits and restrictions that brings. An example of a benefit is proper interoperability with classes written in other languages (for example, a managed C++ class can inherit from a Visual Basic class). An example of a restriction is that a managed class can only inherit from one base class.
The Microsoft .NET Framework is a platform for building, deploying, and running Web Services and applications. It provides a highly productive, standards-based, multi-language environment for integrating existing investments with next-generation applications and services as well as the agility to solve the challenges of deployment and operation of Internet-scale applications. The .NET Framework consists of three main parts: the common language runtime, a hierarchical set of unified class libraries, and a componentized version of Active Server Pages called
ASP.NET.
How many languages .NET is supporting now?
When .NET was introduced it came with several languages. VB.NET, C#, COBOL and Perl, etc. The site DotNetLanguages.Net says 44 languages are supported.
How is .NET able to support multiple languages?
.Net is a language should comply with the Common Language Runtime standard to become a .NET language. In .NET, code is compiled to Microsoft Intermediate Language (MSIL for short). This is called as Managed Code. This Managed code is run in .NET environment. So after compilation to this IL the language is not a barrier. A code can call or use a function written in another language.
Runtime Technical Questions
Terminology
What is the common language runtime (CLR)?
The common language runtime is the execution engine for .NET Framework applications.
It provides a number of services, including the following:
Code management (loading and execution)
Application memory isolation
Verification of type safety
Conversion of IL to native code
Access to metadata (enhanced type information)
Managing memory for managed objects
Enforcement of code access security
Exception handling, including cross-language exceptions
Interoperation between managed code, COM objects, and pre-existing DLLs (unmanaged code
and data)
Automation of object layout
Support for developer services (profiling, debugging, and so on)
What is the common type system (CTS)?
The common type system is a rich type system, built into the common language runtime, that supports the types and operations found in most programming languages. The common type system supports the complete implementation of a wide range of programming languages.
What is the Common Language Specification (CLS)?
The Common Language Specification is a set of constructs and constraints that serves as a guide for library writers and compiler writers. It allows libraries to be fully usable from any language supporting the CLS, and for those languages to integrate with each other. The Common Language Specification is a subset of the common type system. The Common Language Specification is also important to application developers who are writing code that will be used by other developers. When developers design publicly accessible APIs following the rules of the CLS, those APIs are easily used from all other programming languages that target the common language runtime.
What is the Microsoft Intermediate Language (MSIL)?
MSIL is the CPU-independent instruction set into which .NET Framework programs are compiled. It contains instructions for loading, storing, initializing, and calling methods on objects. Combined with metadata and the common type system, MSIL allows for true cross-language integration. Prior to execution, MSIL is converted to machine code. It is not interpreted.
What is managed code and managed data?
Managed code is code that is written to target the services of the common language runtime (see What is the Common Language Runtime?). In order to target these services, the code must provide a minimum level of information (metadata) to the runtime. All C#, Visual Basic .NET, and JScript .NET code is managed by default. Visual Studio .NET C++ code is not managed by default, but the compiler can produce managed code by specifying a command-line switch (/CLR). Closely related to managed code is managed data--data that is allocated and de-allocated by the common language runtime's garbage collector. C#, Visual Basic, and JScript .NET data is
managed by default. C# data can, however, be marked as unmanaged through the use of special keywords. Visual Studio .NET C++ data is unmanaged by default (even when using the /CLR switch), but when using Managed Extensions for C++, a class can be marked as managed by using the __gc keyword. As the name suggests, this means that the memory for instances of the class is managed by the garbage collector. In addition, the class becomes a full participating member of the .NET Framework community, with the benefits and restrictions that brings. An example of a benefit is proper interoperability with classes written in other languages (for example, a managed C++ class can inherit from a Visual Basic class). An example of a restriction is that a managed class can only inherit from one base class.
dot net free interview questions see
This is a list of questions I have gathered and created over a period of time from my experience, many of which I felt where incomplete or simply wrong. I have finally taken the time to go through each question and correct them to the best of my ability. However, please feel free to post feedback to challenge, improve, or suggest new questions. I want to thank those of you that have contributed quality questions and corrections thus far.
There are some questions in this list that I do not consider to be good questions for an interview. However, they do exist on other lists available on the Internet so I felt compelled to keep them here for easy access.
1.
Describe the role of inetinfo.exe, aspnet_isapi.dll andaspnet_wp.exe in the page loading process.
inetinfo.exe is theMicrosoft IIS server running, handling ASP.NET requests among other things.When an ASP.NET request is received (usually a file with .aspx extension), the ISAPI filter aspnet_isapi.dll takes care of it by passing the request tothe actual worker process aspnet_wp.exe.
2. What’s the difference between Response.Write() andResponse.Output.Write()?
Response.Output.Write() allows you to write formatted output.
3. What methods are fired during the page load?
Init() - when the page is instantiated
Load() - when the page is loaded into server memory
PreRender() - the brief moment before the page is displayed to the user as HTML
Unload() - when page finishes loading.
4. When during the page processing cycle is ViewState available?
After the Init() and before the Page_Load(), or OnLoad() for a control.
5. What namespace does the Web page belong in the .NET Framework class hierarchy?
System.Web.UI.Page
6. Where do you store the information about the user’s locale?
System.Web.UI.Page.Culture
7. What’s the difference between Codebehind="MyCode.aspx.cs" andSrc="MyCode.aspx.cs"?
CodeBehind is relevant to Visual Studio.NET only.
8. What’s a bubbled event?
When you have a complex control, like DataGrid, writing an event processing routine for each object (cell, button, row, etc.) is quite tedious. The controls can bubble up their eventhandlers, allowing the main DataGrid event handler to take care of its constituents.
9. Suppose you want a certain ASP.NET function executed on MouseOver for a certain button. Where do you add an event handler?
Add an OnMouseOver attribute to the button. Example: btnSubmit.Attributes.Add("onmouseover","someClientCodeHere();");
10. What data types do the RangeValidator control support?
Integer, String, and Date.
11. Explain the differences between Server-side and Client-side code?
Server-side code executes on the server. Client-side code executes in the client's browser.
12. What type of code (server or client) is found in a Code-Behind class?
The answer is server-side code since code-behind is executed on the server. However, during the code-behind's execution on the server, it can render client-side code such as JavaScript to be processed in the clients browser. But just to be clear, code-behind executes on the server, thus making it server-side code.
13. Should user input data validation occur server-side or client-side? Why?
All user input data validation should occur on the server at a minimum. Additionally, client-side validation can be performed where deemed appropriate and feasable to provide a richer, more responsive experience for the user.
14. What is the difference between Server.Transfer and Response.Redirect? Why would I choose one over the other?
Server.Transfer transfers page processing from one page directly to the next page without making a round-trip back to the client's browser. This provides a faster response with a little less overhead on the server. Server.Transfer does not update the clients url history list or current url. Response.Redirect is used to redirect the user's browser to another page or site. This performas a trip back to the client where the client's browser is redirected to the new page. The user's browser history list is updated to reflect the new address.
15. Can you explain the difference between an ADO.NET Dataset and an ADO Recordset?
Valid answers are:
· A DataSet can represent an entire relational database in memory, complete with tables, relations, and views.
· A DataSet is designed to work without any continuing connection to the original data source.
· Data in a DataSet is bulk-loaded, rather than being loaded on demand.
· There's no concept of cursor types in a DataSet.
· DataSets have no current record pointer You can use For Each loops to move through the data.
· You can store many edits in a DataSet, and write them to the original data source in a single operation.
· Though the DataSet is universal, other objects in ADO.NET come in different versions for different data sources.
16. What is the Global.asax used for?
The Global.asax (including the Global.asax.cs file) is used to implement application and session level events.
17. What are the Application_Start and Session_Start subroutines used for?
This is where you can set the specific variables for the Application and Session objects.
18. Can you explain what inheritance is and an example of when you might use it?
When you want to inherit (use the functionality of) another class. Example: With a base class named Employee, a Manager class could be derived from the Employee base class.
19. Whats an assembly?
Assemblies are the building blocks of the .NET framework. Overview of assemblies from MSDN
20. Describe the difference between inline and code behind.
Inline code written along side the html in a page. Code-behind is code written in a separate file and referenced by the .aspx page.
21. Explain what a diffgram is, and a good use for one?
The DiffGram is one of the two XML formats that you can use to render DataSet object contents to XML. A good use is reading database data to an XML file to be sent to a Web Service.
22. Whats MSIL, and why should my developers need an appreciation of it if at all?
MSIL is the Microsoft Intermediate Language. All .NET compatible languages will get converted to MSIL. MSIL also allows the .NET Framework to JIT compile the assembly on the installed computer.
23. Which method do you invoke on the DataAdapter control to load your generated dataset with data?
The Fill() method.
24. Can you edit data in the Repeater control?
No, it just reads the information from its data source.
25. Which template must you provide, in order to display data in a Repeater control?
ItemTemplate.
26. How can you provide an alternating color scheme in a Repeater control?
Use the AlternatingItemTemplate.
27. What property must you set, and what method must you call in your code, in order to bind the data from a data source to the Repeater control?
You must set the DataSource property and call the DataBind method.
28. What base class do all Web Forms inherit from?
The Page class.
29. Name two properties common in every validation control?
ControlToValidate property and Text property.
30. Which property on a Combo Box do you set with a column name, prior to setting the DataSource, to display data in the combo box?
DataTextField property.
31. Which control would you use if you needed to make sure the values in two different controls matched?
CompareValidator control.
32. How many classes can a single .NET DLL contain?
It can contain many classes.
Web Service Questions
1. What is the transport protocol you use to call a Web service?
SOAP (Simple Object Access Protocol) is the preferred protocol.
2. True or False: A Web service can only be written in .NET?
False
3. What does WSDL stand for?
Web Services Description Language.
4. Where on the Internet would you look for Web services?
http://www.uddi.org
5. True or False: To test a Web service you must create a Windows application or Web application to consume this service?
False, the web service comes with a test page and it provides HTTP-GET method to test.
State Management Questions
1. What is ViewState?
ViewState allows the state of objects (serializable) to be stored in a hidden field on the page. ViewState is transported to the client and back to the server, and is not stored on the server or any other external source. ViewState is used the retain the state of server-side objects between postabacks.
2. What is the lifespan for items stored in ViewState?
Item stored in ViewState exist for the life of the current page. This includes postbacks (to the same page).
3. What does the "EnableViewState" property do? Why would I want it on or off?
It allows the page to save the users input on a form across postbacks. It saves the server-side values for a given control into ViewState, which is stored as a hidden value on the page before sending the page to the clients browser. When the page is posted back to the server the server control is recreated with the state stored in viewstate.
4. What are the different types of Session state management options available with ASP.NET?
ASP.NET provides In-Process and Out-of-Process state management. In-Process stores the session in memory on the web server. This requires the a "sticky-server" (or no load-balancing) so that the user is always reconnected to the same web server. Out-of-Process Session state management stores data in an external data source. The external data source may be either a SQL Server or a State Server service. Out-of-Process state management requires that all objects stored in session are serializable.
posted on Tuesday, March 16, 2004 8:14 AM
Feedback
# re: Interview Questions: ASP.NET 6/1/2004 5:00 AM pinak
hey can anyone gimme some common basic questions on .net which can b expected in interview. Plz consider that i'm just beginer in .net. You can mail me at
pinak222@yahoo.com. I'll b really thankfull to u ...
bye
# re: Interview Questions: ASP.NET 6/25/2004 11:08 PM thomas
hello friend
thankx for you questions.
the questions seems to be little bit tough, so if you have prilim questions for a beginner, could you please send it to me.
with prayers..........................................thomas
thomasjames_code@yahoo.co.in
# re: Interview Questions: ASP.NET 7/1/2004 12:49 AM doubt
11. What type of code (server or client) is found in a Code-Behind class? Server-side code.
we can write client side code in code-behind calss like
button1.Attributes.Add("onMouseOver", "window.open('webform1.aspx')")
pls help me
# re: Interview Questions: ASP.NET 7/1/2004 12:44 PM Mark Wagner
You are correct. You can write dynamically created client-side code in the code-behind class just as you have shown in your example. I understand your question and believe you have a good point. However, I would argue the code-behind class should still be considered "server-side" code since that is where it is executing. Client-side code does not execute in the code-behind, it is simply text or data, not really code and is treated as such in the code-behind.
Your (excellent) example demonstrates the power of ASP in that a developer can dynamically create HTML, XML, or even Javascript in the code-behind. As you have pointed out, this dynamically generated code would execute on the client-side.
In short, you are correct in your assessment and appear to be able to intelligently answer this question should you encounter it in an interview. Great question!
# re: Interview Questions: ASP.NET 7/3/2004 10:36 AM Yasser
Hi,
This is in response to Question 12, validation should occur on client side and server side both. Client side should happen to avoid server round trip, but it's easily possible to by-pass client side validation. Say if someone has turned of javascript in her browser or if the browser is not supporting javascript? In that scenario client side validation will not work. Hence if the validation is also done on server than such scenario can be avoided. The rule is whether validation occurs on client or not, but it should always occur on server.
# re: Interview Questions: ASP.NET 7/5/2004 10:26 PM Vivek Kumbhojkar
This article is realyy good for beginners..
Excellent article
Vivek
# re: Interview Questions: ASP.NET 7/16/2004 11:00 PM vishal wadhawan
This is a real good stuff.I liked it very much and i'll refer it to every fresher.
# re: Interview Questions: ASP.NET 7/20/2004 3:02 AM Rohit Kalia
This is in response to Question 14 : What is the difference between Server.Transfer and Response.Redirect? Why would I choose one over the other?
server.transfer simply transfer execution to another page. this doesn't require any information to be sent to the browser== it all occurs on the server without the user's knowledge.
The response.redirect method sends http information to the browser instructing it to go to another page.
rohitkalya@yahoo.com
# re: Interview Questions: ASP.NET 7/29/2004 11:31 AM Mukti ranjan
It's very very useful for interview purpose. thanks for this good did.
# re: Interview Questions: ASP.NET 7/29/2004 11:07 PM vishal
hi all
I,m working in NIC .it's a very good question for all freshers who really want about the .net
# re: Interview Questions: ASP.NET 8/5/2004 12:01 AM sandy
hi all,
i think these questions r very much useful for freshers,but it will be more useful if u provide more questions on this topic
bye to all
sandy
# re: Interview Questions: ASP.NET 8/5/2004 9:05 PM Akhil Bhandari
Good Stuff!!
Flood it with more....
# re: Interview Questions: ASP.NET 8/8/2004 11:04 PM Fahad Khalil
Hi
About question 12... the validation on client side. Yes, one should perform the validation on client side... but as they say, *never trust your client, specially thin*.
So always perform validation on client side, try to save atleast one trip. If client is not messing with the HTML, then he is doing a favor on himself. If he is messing, let him waste his own band width.
To check whether all the validors on a page validate into *true*, before performing business, you better should do...
Page.IsValid
or if you want to perform validation for a particular validator, just do...
FieldValidator.IsValid.
Hope this helps :)
There are some questions in this list that I do not consider to be good questions for an interview. However, they do exist on other lists available on the Internet so I felt compelled to keep them here for easy access.
1.
Describe the role of inetinfo.exe, aspnet_isapi.dll andaspnet_wp.exe in the page loading process.
inetinfo.exe is theMicrosoft IIS server running, handling ASP.NET requests among other things.When an ASP.NET request is received (usually a file with .aspx extension), the ISAPI filter aspnet_isapi.dll takes care of it by passing the request tothe actual worker process aspnet_wp.exe.
2. What’s the difference between Response.Write() andResponse.Output.Write()?
Response.Output.Write() allows you to write formatted output.
3. What methods are fired during the page load?
Init() - when the page is instantiated
Load() - when the page is loaded into server memory
PreRender() - the brief moment before the page is displayed to the user as HTML
Unload() - when page finishes loading.
4. When during the page processing cycle is ViewState available?
After the Init() and before the Page_Load(), or OnLoad() for a control.
5. What namespace does the Web page belong in the .NET Framework class hierarchy?
System.Web.UI.Page
6. Where do you store the information about the user’s locale?
System.Web.UI.Page.Culture
7. What’s the difference between Codebehind="MyCode.aspx.cs" andSrc="MyCode.aspx.cs"?
CodeBehind is relevant to Visual Studio.NET only.
8. What’s a bubbled event?
When you have a complex control, like DataGrid, writing an event processing routine for each object (cell, button, row, etc.) is quite tedious. The controls can bubble up their eventhandlers, allowing the main DataGrid event handler to take care of its constituents.
9. Suppose you want a certain ASP.NET function executed on MouseOver for a certain button. Where do you add an event handler?
Add an OnMouseOver attribute to the button. Example: btnSubmit.Attributes.Add("onmouseover","someClientCodeHere();");
10. What data types do the RangeValidator control support?
Integer, String, and Date.
11. Explain the differences between Server-side and Client-side code?
Server-side code executes on the server. Client-side code executes in the client's browser.
12. What type of code (server or client) is found in a Code-Behind class?
The answer is server-side code since code-behind is executed on the server. However, during the code-behind's execution on the server, it can render client-side code such as JavaScript to be processed in the clients browser. But just to be clear, code-behind executes on the server, thus making it server-side code.
13. Should user input data validation occur server-side or client-side? Why?
All user input data validation should occur on the server at a minimum. Additionally, client-side validation can be performed where deemed appropriate and feasable to provide a richer, more responsive experience for the user.
14. What is the difference between Server.Transfer and Response.Redirect? Why would I choose one over the other?
Server.Transfer transfers page processing from one page directly to the next page without making a round-trip back to the client's browser. This provides a faster response with a little less overhead on the server. Server.Transfer does not update the clients url history list or current url. Response.Redirect is used to redirect the user's browser to another page or site. This performas a trip back to the client where the client's browser is redirected to the new page. The user's browser history list is updated to reflect the new address.
15. Can you explain the difference between an ADO.NET Dataset and an ADO Recordset?
Valid answers are:
· A DataSet can represent an entire relational database in memory, complete with tables, relations, and views.
· A DataSet is designed to work without any continuing connection to the original data source.
· Data in a DataSet is bulk-loaded, rather than being loaded on demand.
· There's no concept of cursor types in a DataSet.
· DataSets have no current record pointer You can use For Each loops to move through the data.
· You can store many edits in a DataSet, and write them to the original data source in a single operation.
· Though the DataSet is universal, other objects in ADO.NET come in different versions for different data sources.
16. What is the Global.asax used for?
The Global.asax (including the Global.asax.cs file) is used to implement application and session level events.
17. What are the Application_Start and Session_Start subroutines used for?
This is where you can set the specific variables for the Application and Session objects.
18. Can you explain what inheritance is and an example of when you might use it?
When you want to inherit (use the functionality of) another class. Example: With a base class named Employee, a Manager class could be derived from the Employee base class.
19. Whats an assembly?
Assemblies are the building blocks of the .NET framework. Overview of assemblies from MSDN
20. Describe the difference between inline and code behind.
Inline code written along side the html in a page. Code-behind is code written in a separate file and referenced by the .aspx page.
21. Explain what a diffgram is, and a good use for one?
The DiffGram is one of the two XML formats that you can use to render DataSet object contents to XML. A good use is reading database data to an XML file to be sent to a Web Service.
22. Whats MSIL, and why should my developers need an appreciation of it if at all?
MSIL is the Microsoft Intermediate Language. All .NET compatible languages will get converted to MSIL. MSIL also allows the .NET Framework to JIT compile the assembly on the installed computer.
23. Which method do you invoke on the DataAdapter control to load your generated dataset with data?
The Fill() method.
24. Can you edit data in the Repeater control?
No, it just reads the information from its data source.
25. Which template must you provide, in order to display data in a Repeater control?
ItemTemplate.
26. How can you provide an alternating color scheme in a Repeater control?
Use the AlternatingItemTemplate.
27. What property must you set, and what method must you call in your code, in order to bind the data from a data source to the Repeater control?
You must set the DataSource property and call the DataBind method.
28. What base class do all Web Forms inherit from?
The Page class.
29. Name two properties common in every validation control?
ControlToValidate property and Text property.
30. Which property on a Combo Box do you set with a column name, prior to setting the DataSource, to display data in the combo box?
DataTextField property.
31. Which control would you use if you needed to make sure the values in two different controls matched?
CompareValidator control.
32. How many classes can a single .NET DLL contain?
It can contain many classes.
Web Service Questions
1. What is the transport protocol you use to call a Web service?
SOAP (Simple Object Access Protocol) is the preferred protocol.
2. True or False: A Web service can only be written in .NET?
False
3. What does WSDL stand for?
Web Services Description Language.
4. Where on the Internet would you look for Web services?
http://www.uddi.org
5. True or False: To test a Web service you must create a Windows application or Web application to consume this service?
False, the web service comes with a test page and it provides HTTP-GET method to test.
State Management Questions
1. What is ViewState?
ViewState allows the state of objects (serializable) to be stored in a hidden field on the page. ViewState is transported to the client and back to the server, and is not stored on the server or any other external source. ViewState is used the retain the state of server-side objects between postabacks.
2. What is the lifespan for items stored in ViewState?
Item stored in ViewState exist for the life of the current page. This includes postbacks (to the same page).
3. What does the "EnableViewState" property do? Why would I want it on or off?
It allows the page to save the users input on a form across postbacks. It saves the server-side values for a given control into ViewState, which is stored as a hidden value on the page before sending the page to the clients browser. When the page is posted back to the server the server control is recreated with the state stored in viewstate.
4. What are the different types of Session state management options available with ASP.NET?
ASP.NET provides In-Process and Out-of-Process state management. In-Process stores the session in memory on the web server. This requires the a "sticky-server" (or no load-balancing) so that the user is always reconnected to the same web server. Out-of-Process Session state management stores data in an external data source. The external data source may be either a SQL Server or a State Server service. Out-of-Process state management requires that all objects stored in session are serializable.
posted on Tuesday, March 16, 2004 8:14 AM
Feedback
# re: Interview Questions: ASP.NET 6/1/2004 5:00 AM pinak
hey can anyone gimme some common basic questions on .net which can b expected in interview. Plz consider that i'm just beginer in .net. You can mail me at
pinak222@yahoo.com. I'll b really thankfull to u ...
bye
# re: Interview Questions: ASP.NET 6/25/2004 11:08 PM thomas
hello friend
thankx for you questions.
the questions seems to be little bit tough, so if you have prilim questions for a beginner, could you please send it to me.
with prayers..........................................thomas
thomasjames_code@yahoo.co.in
# re: Interview Questions: ASP.NET 7/1/2004 12:49 AM doubt
11. What type of code (server or client) is found in a Code-Behind class? Server-side code.
we can write client side code in code-behind calss like
button1.Attributes.Add("onMouseOver", "window.open('webform1.aspx')")
pls help me
# re: Interview Questions: ASP.NET 7/1/2004 12:44 PM Mark Wagner
You are correct. You can write dynamically created client-side code in the code-behind class just as you have shown in your example. I understand your question and believe you have a good point. However, I would argue the code-behind class should still be considered "server-side" code since that is where it is executing. Client-side code does not execute in the code-behind, it is simply text or data, not really code and is treated as such in the code-behind.
Your (excellent) example demonstrates the power of ASP in that a developer can dynamically create HTML, XML, or even Javascript in the code-behind. As you have pointed out, this dynamically generated code would execute on the client-side.
In short, you are correct in your assessment and appear to be able to intelligently answer this question should you encounter it in an interview. Great question!
# re: Interview Questions: ASP.NET 7/3/2004 10:36 AM Yasser
Hi,
This is in response to Question 12, validation should occur on client side and server side both. Client side should happen to avoid server round trip, but it's easily possible to by-pass client side validation. Say if someone has turned of javascript in her browser or if the browser is not supporting javascript? In that scenario client side validation will not work. Hence if the validation is also done on server than such scenario can be avoided. The rule is whether validation occurs on client or not, but it should always occur on server.
# re: Interview Questions: ASP.NET 7/5/2004 10:26 PM Vivek Kumbhojkar
This article is realyy good for beginners..
Excellent article
Vivek
# re: Interview Questions: ASP.NET 7/16/2004 11:00 PM vishal wadhawan
This is a real good stuff.I liked it very much and i'll refer it to every fresher.
# re: Interview Questions: ASP.NET 7/20/2004 3:02 AM Rohit Kalia
This is in response to Question 14 : What is the difference between Server.Transfer and Response.Redirect? Why would I choose one over the other?
server.transfer simply transfer execution to another page. this doesn't require any information to be sent to the browser== it all occurs on the server without the user's knowledge.
The response.redirect method sends http information to the browser instructing it to go to another page.
rohitkalya@yahoo.com
# re: Interview Questions: ASP.NET 7/29/2004 11:31 AM Mukti ranjan
It's very very useful for interview purpose. thanks for this good did.
# re: Interview Questions: ASP.NET 7/29/2004 11:07 PM vishal
hi all
I,m working in NIC .it's a very good question for all freshers who really want about the .net
# re: Interview Questions: ASP.NET 8/5/2004 12:01 AM sandy
hi all,
i think these questions r very much useful for freshers,but it will be more useful if u provide more questions on this topic
bye to all
sandy
# re: Interview Questions: ASP.NET 8/5/2004 9:05 PM Akhil Bhandari
Good Stuff!!
Flood it with more....
# re: Interview Questions: ASP.NET 8/8/2004 11:04 PM Fahad Khalil
Hi
About question 12... the validation on client side. Yes, one should perform the validation on client side... but as they say, *never trust your client, specially thin*.
So always perform validation on client side, try to save atleast one trip. If client is not messing with the HTML, then he is doing a favor on himself. If he is messing, let him waste his own band width.
To check whether all the validors on a page validate into *true*, before performing business, you better should do...
Page.IsValid
or if you want to perform validation for a particular validator, just do...
FieldValidator.IsValid.
Hope this helps :)
General C# Interview Questions :
Difference between value and reference type. what are value types and reference types?
Value type - bool, byte, chat, decimal, double, enum , float, int, long, sbyte, short, strut, uint, ulong, ushort
Value types are stored in the Stack
Reference type - class, delegate, interface, object, string
Reference types are stored in the Heap
What are the two kinds of properties.
Two types of properties in .Net: Get and Set
Explain constructor.
Constructor is a method in the class which has the same name as the class (in VB.Net its New()). It initializes the member attributes whenever an instance of the class is created.
Describe ways of cleaning up objects.
Answer1
There is a perfect tool provide by .net frameworks calls Garbage collector, where by mean of GC we can clean up the object and reclaim the memory. The namespace used is System.GC
Answer2
the run time will maintain a service called as garbage collector. This service will take care of deallocating memory corresponding to objects. it works as a thread with least priority. when application demands for memory the runtime will take care of setting the high priority for the garbage collector, so that it will be called for execution and memory will be released. the programmer can make a call to garbage collector by using GC class in system name space.
How can you clean up objects holding resources from within the code?
Call the dispose method from code for clean up of objects
Which controls do not have events?
Timer control.
What is the maximum size of the textbox?
65536.
Which property of the textbox cannot be changed at runtime?
Locked Property.
Which control cannot be placed in MDI?
The controls that do not have events.
What is the difference between proc. sent BY VAL and BY SUB?
BY VAL: changes will not be reflected back to the variable.
By REF: changes will be reflected back to that variable.( same as & symbol in c, c++)
General C# Interview Questions :
Does C# support multiple-inheritance?
No.
Who is a protected class-level variable available to?
It is available to any sub-class (a class inheriting this class).
Are private class-level variables inherited?
Yes, but they are not accessible. Although they are not visible or accessible via the class interface, they are inherited.
Describe the accessibility modifier “protected internal”.
It is available to classes that are within the same assembly and derived from the specified base class.
What’s the top .NET class that everything is derived from?
System.Object.
What does the term immutable mean?
The data value may not be changed. Note: The variable value may be changed, but the original immutable data value was discarded and a new data value was created in memory.
What’s the difference between System.String and System.Text.StringBuilder classes?
System.String is immutable. System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed.
What’s the advantage of using System.Text.StringBuilder over System.String?
StringBuilder is more efficient in cases where there is a large amount of string manipulation. Strings are immutable, so each time a string is changed, a new instance in memory is created.
Can you store multiple data types in System.Array?
No.
What’s the difference between the System.Array.CopyTo() and System.Array.Clone()?
The Clone() method returns a new array (a shallow copy) object containing all the elements in the original array. The CopyTo() method copies the elements into another existing array. Both perform a shallow copy. A shallow copy means the contents (each array element) contains references to the same object as the elements in the original array. A deep copy (which neither of these methods performs) would create a new instance of each element's object, resulting in a different, yet identical object.
How can you sort the elements of the array in descending order?
By calling Sort() and then Reverse() methods.
Value type - bool, byte, chat, decimal, double, enum , float, int, long, sbyte, short, strut, uint, ulong, ushort
Value types are stored in the Stack
Reference type - class, delegate, interface, object, string
Reference types are stored in the Heap
What are the two kinds of properties.
Two types of properties in .Net: Get and Set
Explain constructor.
Constructor is a method in the class which has the same name as the class (in VB.Net its New()). It initializes the member attributes whenever an instance of the class is created.
Describe ways of cleaning up objects.
Answer1
There is a perfect tool provide by .net frameworks calls Garbage collector, where by mean of GC we can clean up the object and reclaim the memory. The namespace used is System.GC
Answer2
the run time will maintain a service called as garbage collector. This service will take care of deallocating memory corresponding to objects. it works as a thread with least priority. when application demands for memory the runtime will take care of setting the high priority for the garbage collector, so that it will be called for execution and memory will be released. the programmer can make a call to garbage collector by using GC class in system name space.
How can you clean up objects holding resources from within the code?
Call the dispose method from code for clean up of objects
Which controls do not have events?
Timer control.
What is the maximum size of the textbox?
65536.
Which property of the textbox cannot be changed at runtime?
Locked Property.
Which control cannot be placed in MDI?
The controls that do not have events.
What is the difference between proc. sent BY VAL and BY SUB?
BY VAL: changes will not be reflected back to the variable.
By REF: changes will be reflected back to that variable.( same as & symbol in c, c++)
General C# Interview Questions :
Does C# support multiple-inheritance?
No.
Who is a protected class-level variable available to?
It is available to any sub-class (a class inheriting this class).
Are private class-level variables inherited?
Yes, but they are not accessible. Although they are not visible or accessible via the class interface, they are inherited.
Describe the accessibility modifier “protected internal”.
It is available to classes that are within the same assembly and derived from the specified base class.
What’s the top .NET class that everything is derived from?
System.Object.
What does the term immutable mean?
The data value may not be changed. Note: The variable value may be changed, but the original immutable data value was discarded and a new data value was created in memory.
What’s the difference between System.String and System.Text.StringBuilder classes?
System.String is immutable. System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed.
What’s the advantage of using System.Text.StringBuilder over System.String?
StringBuilder is more efficient in cases where there is a large amount of string manipulation. Strings are immutable, so each time a string is changed, a new instance in memory is created.
Can you store multiple data types in System.Array?
No.
What’s the difference between the System.Array.CopyTo() and System.Array.Clone()?
The Clone() method returns a new array (a shallow copy) object containing all the elements in the original array. The CopyTo() method copies the elements into another existing array. Both perform a shallow copy. A shallow copy means the contents (each array element) contains references to the same object as the elements in the original array. A deep copy (which neither of these methods performs) would create a new instance of each element's object, resulting in a different, yet identical object.
How can you sort the elements of the array in descending order?
By calling Sort() and then Reverse() methods.
C# Interview Questions and Answers 15
What namespaces are necessary to create a localized application?
System.Globalization and System.Resources.
What is the smallest unit of execution in .NET?
an Assembly.
When should you call the garbage collector in .NET?
As a good rule, you should not call the garbage collector. However, you could call the garbage collector when you are done using a large object (or set of objects) to force the garbage collector to dispose of those very large objects from memory. However, this is usually not a good practice.
How do you convert a value-type to a reference-type?
Use Boxing.
What happens in memory when you Box and Unbox a value-type?
Boxing converts a value-type to a reference-type, thus storing the object on the heap. Unboxing converts a reference-type to a value-type, thus storing the value on the stack.Difference between directcast and ctype.
Answer1
DirectCast requires the run-time type of an object variable to bethe same as the specified type.The run-time performance ofDirectCast is better than that of CType, if the specified type and the run-time typeof the expression are the same. Ctype works fine if there is a valid conversion defined between the expression and the type.
Answer2
The difference between the two keywords is that CType succeeds as long as there is a valid conversion defined between the expression and the type, whereas DirectCast requires the run-time type of an object variable to be the same as the specified type. If the specified type and the run-time type of the expression are the same, however, the run-time performance of DirectCast is better than that of CType.
An example of a ctype and directcast.
In the preceding example, the run-time type of Q is Double. CType succeeds because Double can be converted to Integer, but DirectCast fails because the run-time type of Q is not already Integer
ctype(123.34,integer) - should it throw an error? Why or why not?
Answer1
It would work fine. As the runtime type of 123.34 would be double, and Double can be converted to Integer.
Answer2
the ctype(123.34,integer) will work fine no errors
directcast(123.34,integer) - should it throw an error? Why or why not?
It would throw an InvalidCast exception as the runtime type of 123.34 (double) doesnt match with Integer.
Difference between a sub and a function.
Answer1
A Sub does not return anything whereas a Function returns something.
Answer2
-A Sub Procedure is a method will not return a value
-A sub procedure will be defined with a “Sub” keyword
Sub ShowName(ByVal myName As String)
Console.WriteLine(”My name is: ” & myName)
End Sub
-A function is a method that will return value(s).
-A function will be defined with a “Function” keyword
Function FindSum(ByVal num1 As Integer, ByVal num2 As Integer) As Integer
Dim sum As Integer = num1 + num2
Return sum
End Function
Explain manifest & metadata.
Answer1
Manifest is metadata about assemblies. Metadata is machine-readable information about a resource, or “”data about data.” In .NET, metadata includes type definitions, version information, external assembly references, and other standardized information.
Answer2
Manifest: Manifest describes assembly itself. Assembly Name, version number, culture, strong name, list of all files, Type references, and referenced assemblies.
Metadata: Metadata describes contents in an assembly classes, interfaces, enums, structs, etc., and their containing namespaces, the name of each type, its visibility/scope, its base class, the nterfaces it implemented, its methods and their scope, and each method’s parameters, type’s properties, and so on.
Difference between imperative and interrogative code.
There are imperative and interrogative functions. Imperative functions are the one which return a value while the interrogative functions do not return a value.
System.Globalization and System.Resources.
What is the smallest unit of execution in .NET?
an Assembly.
When should you call the garbage collector in .NET?
As a good rule, you should not call the garbage collector. However, you could call the garbage collector when you are done using a large object (or set of objects) to force the garbage collector to dispose of those very large objects from memory. However, this is usually not a good practice.
How do you convert a value-type to a reference-type?
Use Boxing.
What happens in memory when you Box and Unbox a value-type?
Boxing converts a value-type to a reference-type, thus storing the object on the heap. Unboxing converts a reference-type to a value-type, thus storing the value on the stack.Difference between directcast and ctype.
Answer1
DirectCast requires the run-time type of an object variable to bethe same as the specified type.The run-time performance ofDirectCast is better than that of CType, if the specified type and the run-time typeof the expression are the same. Ctype works fine if there is a valid conversion defined between the expression and the type.
Answer2
The difference between the two keywords is that CType succeeds as long as there is a valid conversion defined between the expression and the type, whereas DirectCast requires the run-time type of an object variable to be the same as the specified type. If the specified type and the run-time type of the expression are the same, however, the run-time performance of DirectCast is better than that of CType.
An example of a ctype and directcast.
In the preceding example, the run-time type of Q is Double. CType succeeds because Double can be converted to Integer, but DirectCast fails because the run-time type of Q is not already Integer
ctype(123.34,integer) - should it throw an error? Why or why not?
Answer1
It would work fine. As the runtime type of 123.34 would be double, and Double can be converted to Integer.
Answer2
the ctype(123.34,integer) will work fine no errors
directcast(123.34,integer) - should it throw an error? Why or why not?
It would throw an InvalidCast exception as the runtime type of 123.34 (double) doesnt match with Integer.
Difference between a sub and a function.
Answer1
A Sub does not return anything whereas a Function returns something.
Answer2
-A Sub Procedure is a method will not return a value
-A sub procedure will be defined with a “Sub” keyword
Sub ShowName(ByVal myName As String)
Console.WriteLine(”My name is: ” & myName)
End Sub
-A function is a method that will return value(s).
-A function will be defined with a “Function” keyword
Function FindSum(ByVal num1 As Integer, ByVal num2 As Integer) As Integer
Dim sum As Integer = num1 + num2
Return sum
End Function
Explain manifest & metadata.
Answer1
Manifest is metadata about assemblies. Metadata is machine-readable information about a resource, or “”data about data.” In .NET, metadata includes type definitions, version information, external assembly references, and other standardized information.
Answer2
Manifest: Manifest describes assembly itself. Assembly Name, version number, culture, strong name, list of all files, Type references, and referenced assemblies.
Metadata: Metadata describes contents in an assembly classes, interfaces, enums, structs, etc., and their containing namespaces, the name of each type, its visibility/scope, its base class, the nterfaces it implemented, its methods and their scope, and each method’s parameters, type’s properties, and so on.
Difference between imperative and interrogative code.
There are imperative and interrogative functions. Imperative functions are the one which return a value while the interrogative functions do not return a value.
C# Interview Questions and Answers 14
Why are there five tracing levels in System.Diagnostics.TraceSwitcher?
The tracing dumps can be quite verbose. For applications that are constantly running you run the risk of overloading the machine and the hard drive. Five levels range from None to Verbose, allowing you to fine-tune the tracing activities.
Where is the output of TextWriterTraceListener redirected?
To the Console or a text file depending on the parameter passed to the constructor.
How do you debug an ASP.NET Web application?
Attach the aspnet_wp.exe process to the DbgClr debugger.
What are three test cases you should go through in unit testing?
1. Positive test cases (correct data, correct output).
2. Negative test cases (broken or missing data, proper handling).
3. Exception test cases (exceptions are thrown and caught properly).
Can you change the value of a variable while debugging a C# application?
Yes. If you are debugging via Visual Studio.NET, just go to Immediate window.
What is the role of the DataReader class in ADO.NET connections?
It returns a read-only, forward-only rowset from the data source. A DataReader provides fast access when a forward-only sequential read is needed.What are advantages and disadvantages of Microsoft-provided data provider classes in ADO.NET?
SQLServer.NET data provider is high-speed and robust, but requires SQL Server license purchased from Microsoft. OLE-DB.NET is universal for accessing other sources, like Oracle, DB2, Microsoft Access and Informix. OLE-DB.NET is a .NET layer on top of the OLE layer, so it’s not as fastest and efficient as SqlServer.NET.
What is the wildcard character in SQL?
Let’s say you want to query database with LIKE for all employees whose name starts with La. The wildcard character is %, the proper query with LIKE would involve ‘La%’.
Explain ACID rule of thumb for transactions.
A transaction must be:
1. Atomic - it is one unit of work and does not dependent on previous and following transactions.
2. Consistent - data is either committed or roll back, no “in-between” case where something has been updated and something hasn’t.
3. Isolated - no transaction sees the intermediate results of the current transaction).
4. Durable - the values persist if the data had been committed even if the system crashes right after.
What connections does Microsoft SQL Server support?
Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft SQL Server username and password).
Between Windows Authentication and SQL Server Authentication, which one is trusted and which one is untrusted?
Windows Authentication is trusted because the username and password are checked with the Active Directory, the SQL Server authentication is untrusted, since SQL Server is the only verifier participating in the transaction.
What does the Initial Catalog parameter define in the connection string?
The database name to connect to.
What does the Dispose method do with the connection object?
Deletes it from the memory.
What is a pre-requisite for connection pooling?
Multiple processes must agree that they will share the same connection, where every parameter is the same, including the security settings. The connection string must be identical.
How is the DLL Hell problem solved in .NET?
Assembly versioning allows the application to specify not only the library it needs to run (which was available under Win32), but also the version of the assembly.
What are the ways to deploy an assembly?
An MSI installer, a CAB archive, and XCOPY command.
What is a satellite assembly?
When you write a multilingual or multi-cultural application in .NET, and want to distribute the core application separately from the localized modules, the localized assemblies that modify the core application are called satellite assemblies.
The tracing dumps can be quite verbose. For applications that are constantly running you run the risk of overloading the machine and the hard drive. Five levels range from None to Verbose, allowing you to fine-tune the tracing activities.
Where is the output of TextWriterTraceListener redirected?
To the Console or a text file depending on the parameter passed to the constructor.
How do you debug an ASP.NET Web application?
Attach the aspnet_wp.exe process to the DbgClr debugger.
What are three test cases you should go through in unit testing?
1. Positive test cases (correct data, correct output).
2. Negative test cases (broken or missing data, proper handling).
3. Exception test cases (exceptions are thrown and caught properly).
Can you change the value of a variable while debugging a C# application?
Yes. If you are debugging via Visual Studio.NET, just go to Immediate window.
What is the role of the DataReader class in ADO.NET connections?
It returns a read-only, forward-only rowset from the data source. A DataReader provides fast access when a forward-only sequential read is needed.What are advantages and disadvantages of Microsoft-provided data provider classes in ADO.NET?
SQLServer.NET data provider is high-speed and robust, but requires SQL Server license purchased from Microsoft. OLE-DB.NET is universal for accessing other sources, like Oracle, DB2, Microsoft Access and Informix. OLE-DB.NET is a .NET layer on top of the OLE layer, so it’s not as fastest and efficient as SqlServer.NET.
What is the wildcard character in SQL?
Let’s say you want to query database with LIKE for all employees whose name starts with La. The wildcard character is %, the proper query with LIKE would involve ‘La%’.
Explain ACID rule of thumb for transactions.
A transaction must be:
1. Atomic - it is one unit of work and does not dependent on previous and following transactions.
2. Consistent - data is either committed or roll back, no “in-between” case where something has been updated and something hasn’t.
3. Isolated - no transaction sees the intermediate results of the current transaction).
4. Durable - the values persist if the data had been committed even if the system crashes right after.
What connections does Microsoft SQL Server support?
Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft SQL Server username and password).
Between Windows Authentication and SQL Server Authentication, which one is trusted and which one is untrusted?
Windows Authentication is trusted because the username and password are checked with the Active Directory, the SQL Server authentication is untrusted, since SQL Server is the only verifier participating in the transaction.
What does the Initial Catalog parameter define in the connection string?
The database name to connect to.
What does the Dispose method do with the connection object?
Deletes it from the memory.
What is a pre-requisite for connection pooling?
Multiple processes must agree that they will share the same connection, where every parameter is the same, including the security settings. The connection string must be identical.
How is the DLL Hell problem solved in .NET?
Assembly versioning allows the application to specify not only the library it needs to run (which was available under Win32), but also the version of the assembly.
What are the ways to deploy an assembly?
An MSI installer, a CAB archive, and XCOPY command.
What is a satellite assembly?
When you write a multilingual or multi-cultural application in .NET, and want to distribute the core application separately from the localized modules, the localized assemblies that modify the core application are called satellite assemblies.
C# Interview Questions and Answers 13
What is the syntax to inherit from a class in C#?
Place a colon and then the name of the base class.
Example: class MyNewClass : MyBaseClass
Can you prevent your class from being inherited by another class?
Yes. The keyword “sealed” will prevent the class from being inherited.
Can you allow a class to be inherited, but prevent the method from being over-ridden?
Yes. Just leave the class public and make the method sealed.
What’s an abstract class?
A class that cannot be instantiated. An abstract class is a class that must be inherited and have the methods overridden. An abstract class is essentially a blueprint for a class without any implementation.
When do you absolutely have to declare a class as abstract?
1. When the class itself is inherited from an abstract class, but not all base abstract methods have been overridden.
2. When at least one of the methods in the class is abstract.
What is an interface class?
Interfaces, like classes, define a set of properties, methods, and events. But unlike classes, interfaces do not provide implementation. They are implemented by classes, and defined as separate entities from classes.
Why can’t you specify the accessibility modifier for methods inside the interface?
They all must be public, and are therefore public by default.
What happens if you inherit multiple interfaces and they have conflicting method names?
It’s up to you to implement the method inside your own class, so implementation is left entirely up to you. This might cause a problem on a higher-level scale if similarly named methods from different interfaces expect different data, but as far as compiler cares you’re okay.
To Do: Investigate
What’s the difference between an interface and abstract class?
In an interface class, all methods are abstract - there is no implementation. In an abstract class some methods can be concrete. In an interface class, no accessibility modifiers are allowed. An abstract class may have accessibility modifiers.
What is the difference between a Struct and a Class?
Struts are value-type variables and are thus saved on the stack, additional overhead but faster retrieval. Another difference is that struts cannot inherit.
What’s the implicit name of the parameter that gets passed into the set method/property of a class?
Value. The data type of the value parameter is defined by whatever data type the property is declared as.
What does the keyword “virtual” declare for a method or property?
The method or property can be overridden.
How is method overriding different from method overloading?
When overriding a method, you change the behavior of the method for the derived class. Overloading a method simply involves having another method with the same name within the class.
Can you declare an override method to be static if the original method is not static?
No. The signature of the virtual method must remain the same. (Note: Only the keyword virtual is changed to keyword override)
What are the different ways a method can be overloaded?
Different parameter data types, different number of parameters, different order of parameters.
If a base class has a number of overloaded constructors, and an inheriting class has a number of overloaded constructors; can you enforce a call from an inherited constructor to a specific base constructor?
Yes, just place a colon, and then keyword base (parameter list to invoke the appropriate constructor) in the overloaded constructor definition inside the inherited class.
What’s a delegate?
A delegate object encapsulates a reference to a method.
What’s a multicast delegate?
A delegate that has multiple handlers assigned to it. Each assigned handler (method) is called.
Place a colon and then the name of the base class.
Example: class MyNewClass : MyBaseClass
Can you prevent your class from being inherited by another class?
Yes. The keyword “sealed” will prevent the class from being inherited.
Can you allow a class to be inherited, but prevent the method from being over-ridden?
Yes. Just leave the class public and make the method sealed.
What’s an abstract class?
A class that cannot be instantiated. An abstract class is a class that must be inherited and have the methods overridden. An abstract class is essentially a blueprint for a class without any implementation.
When do you absolutely have to declare a class as abstract?
1. When the class itself is inherited from an abstract class, but not all base abstract methods have been overridden.
2. When at least one of the methods in the class is abstract.
What is an interface class?
Interfaces, like classes, define a set of properties, methods, and events. But unlike classes, interfaces do not provide implementation. They are implemented by classes, and defined as separate entities from classes.
Why can’t you specify the accessibility modifier for methods inside the interface?
They all must be public, and are therefore public by default.
What happens if you inherit multiple interfaces and they have conflicting method names?
It’s up to you to implement the method inside your own class, so implementation is left entirely up to you. This might cause a problem on a higher-level scale if similarly named methods from different interfaces expect different data, but as far as compiler cares you’re okay.
To Do: Investigate
What’s the difference between an interface and abstract class?
In an interface class, all methods are abstract - there is no implementation. In an abstract class some methods can be concrete. In an interface class, no accessibility modifiers are allowed. An abstract class may have accessibility modifiers.
What is the difference between a Struct and a Class?
Struts are value-type variables and are thus saved on the stack, additional overhead but faster retrieval. Another difference is that struts cannot inherit.
What’s the implicit name of the parameter that gets passed into the set method/property of a class?
Value. The data type of the value parameter is defined by whatever data type the property is declared as.
What does the keyword “virtual” declare for a method or property?
The method or property can be overridden.
How is method overriding different from method overloading?
When overriding a method, you change the behavior of the method for the derived class. Overloading a method simply involves having another method with the same name within the class.
Can you declare an override method to be static if the original method is not static?
No. The signature of the virtual method must remain the same. (Note: Only the keyword virtual is changed to keyword override)
What are the different ways a method can be overloaded?
Different parameter data types, different number of parameters, different order of parameters.
If a base class has a number of overloaded constructors, and an inheriting class has a number of overloaded constructors; can you enforce a call from an inherited constructor to a specific base constructor?
Yes, just place a colon, and then keyword base (parameter list to invoke the appropriate constructor) in the overloaded constructor definition inside the inherited class.
What’s a delegate?
A delegate object encapsulates a reference to a method.
What’s a multicast delegate?
A delegate that has multiple handlers assigned to it. Each assigned handler (method) is called.
C# Interview Questions and Answers 12
Why does DllImport not work for me?
All methods marked with the DllImport attribute must be marked as public static extern.
What is a delegate?
A delegate object encapsulates a reference to a method. In C++ they were referred to as function pointers.
What is the difference between an interface and abstract class?
In the interface all methods must be abstract; in the abstract class some methods can be concrete. In the interface no accessibility modifiers are allowed, which is ok in abstract classes.
What is an abstract class?
A class that cannot be instantiated. A concept in C++ known as pure virtual method. A class that must be inherited and have the methods over-ridden. Essentially, it is a blueprint for a class without any implementation.
_break
Does C# support multiple-inheritance?
No.
Who is a protected class-level variable available to?
It is available to any sub-class (a class inheriting this class).
Can you store multiple data types in System.Array?
No.
What’s the top .NET class that everything is derived from?
System.Object.
What does the term immutable mean?
The data value may not be changed. Note: The variable value may be changed, but the original immutable data value was discarded and a new data value was created in memory.
What’s the difference between System.String and System.Text.StringBuilder classes?
System.String is immutable. System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed.
What’s the advantage of using System.Text.StringBuilder over System.String?
StringBuilder is more efficient in cases where there is a large amount of string manipulation. Strings are immutable, so each time a string is changed, a new instance in memory is created.
What’s the difference between the System.Array.CopyTo() and System.Array.Clone()?
The first one performs a deep copy of the array, the second one is shallow. A shallow copy of an Array copies only the elements of the Array, whether they are reference types or value types, but it does not copy the objects that the references refer to. The references in the new Array point to the same objects that the references in the original Array point to. In contrast, a deep copy of an Array copies the elements and everything directly or indirectly referenced by the elements.
How can you sort the elements of the array in descending order?
By calling Sort() and then Reverse() methods.
What’s the .NET collection class that allows an element to be accessed using a unique key?
HashTable.
What class is underneath the SortedList class?
A sorted HashTable.
Will the finally block get executed if an exception has not occurred?
Yes.
What’s the C# syntax to catch any possible exception?
A catch block that catches the exception of type System.Exception. You can also omit the parameter data type in this case and just write catch {}.
Can multiple catch blocks be executed for a single try statement?
No. Once the proper catch block processed, control is transferred to the finally block (if there are any).
Explain the three services model commonly know as a three-tier application.
Presentation (UI), Business (logic and underlying code) and Data (from storage or other sources).
All methods marked with the DllImport attribute must be marked as public static extern.
What is a delegate?
A delegate object encapsulates a reference to a method. In C++ they were referred to as function pointers.
What is the difference between an interface and abstract class?
In the interface all methods must be abstract; in the abstract class some methods can be concrete. In the interface no accessibility modifiers are allowed, which is ok in abstract classes.
What is an abstract class?
A class that cannot be instantiated. A concept in C++ known as pure virtual method. A class that must be inherited and have the methods over-ridden. Essentially, it is a blueprint for a class without any implementation.
_break
Does C# support multiple-inheritance?
No.
Who is a protected class-level variable available to?
It is available to any sub-class (a class inheriting this class).
Can you store multiple data types in System.Array?
No.
What’s the top .NET class that everything is derived from?
System.Object.
What does the term immutable mean?
The data value may not be changed. Note: The variable value may be changed, but the original immutable data value was discarded and a new data value was created in memory.
What’s the difference between System.String and System.Text.StringBuilder classes?
System.String is immutable. System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed.
What’s the advantage of using System.Text.StringBuilder over System.String?
StringBuilder is more efficient in cases where there is a large amount of string manipulation. Strings are immutable, so each time a string is changed, a new instance in memory is created.
What’s the difference between the System.Array.CopyTo() and System.Array.Clone()?
The first one performs a deep copy of the array, the second one is shallow. A shallow copy of an Array copies only the elements of the Array, whether they are reference types or value types, but it does not copy the objects that the references refer to. The references in the new Array point to the same objects that the references in the original Array point to. In contrast, a deep copy of an Array copies the elements and everything directly or indirectly referenced by the elements.
How can you sort the elements of the array in descending order?
By calling Sort() and then Reverse() methods.
What’s the .NET collection class that allows an element to be accessed using a unique key?
HashTable.
What class is underneath the SortedList class?
A sorted HashTable.
Will the finally block get executed if an exception has not occurred?
Yes.
What’s the C# syntax to catch any possible exception?
A catch block that catches the exception of type System.Exception. You can also omit the parameter data type in this case and just write catch {}.
Can multiple catch blocks be executed for a single try statement?
No. Once the proper catch block processed, control is transferred to the finally block (if there are any).
Explain the three services model commonly know as a three-tier application.
Presentation (UI), Business (logic and underlying code) and Data (from storage or other sources).
C# Interview Questions and Answers 11
How do I create a Delegate/MulticastDelegate?
C# requires only a single parameter for delegates: the method address. Unlike other languages, where the programmer must specify an object reference and the method to invoke, C# can infer both pieces of information by just specifying the method's name. For example, let's use System.Threading.ThreadStart: Foo MyFoo = new Foo(); ThreadStart del = new ThreadStart(MyFoo.Baz); This means that delegates can invoke static class methods and instance methods with the exact same syntax!
How do destructors and garbage collection work in C#?
C# has finalizers (similar to destructors except that the runtime doesn't guarantee they'll be called), and they are specified as follows:
class C
{
~C()
{
// your code
}
public static void Main() {}
}
Currently, they override object.Finalize(), which is called during the GC process.
My switch statement works differently! Why?
C# does not support an explicit fall through for case blocks.
The following code is not legal and will not compile in C#: switch(x)
{
case 0:
// do something
case 1:
// do something in common with 0
default:
// do something in common with
//0, 1 and everything else
break;
}
To achieve the same effect in C#, the code must be modified
as shown below (notice how the control flows are explicit): class Test
{
public static void Main()
{
int x = 3;
switch(x)
{
case 0:
// do something
goto case 1;
case 1:
// do something in common with 0
goto default;
default:
// do something in common with 0, 1, and anything else
break;
}
}
}
How can I access the registry from C# code?
By using the Registry and RegistryKey classes in Microsoft.Win32, you can easily access the registry. The following is a sample that reads a key and displays its value:
using System;using Microsoft.Win32;
class regTest
{
public static void Main(String[] args)
{
RegistryKey regKey;
Object value;
regKey = Registry.LocalMachine;
regKey =
regKey.OpenSubKey("HARDWAREDESCRIPTIONSystemCentralProcessor ");
value = regKey.GetValue("VendorIdentifier");
Console.WriteLine("The central processor of this machine is: {0}.", value);
}
}
How can you sort the elements of the array in descending order?
By calling Sort() and then Reverse() methods.
How do you debug an ASP.NET Web application?
Attach the aspnet_wp.exe process to the DbgClr debugger.
How do you mark a method obsolete?
Assuming you've done a "using System;": [Obsolete]
public int Foo() {...}
or [Obsolete("This is a message describing why this method is obsolete")]
public int Foo() {...}
Note: The O in Obsolete is capitalized.
How is the DLL Hell problem solved in .NET?
Assembly versioning allows the application to specify not only the library it needs to run (which was available under Win32), but also the version of the assembly
What are the ways to deploy an assembly?
An MSI installer, a CAB archive, and XCOPY command.
C# requires only a single parameter for delegates: the method address. Unlike other languages, where the programmer must specify an object reference and the method to invoke, C# can infer both pieces of information by just specifying the method's name. For example, let's use System.Threading.ThreadStart: Foo MyFoo = new Foo(); ThreadStart del = new ThreadStart(MyFoo.Baz); This means that delegates can invoke static class methods and instance methods with the exact same syntax!
How do destructors and garbage collection work in C#?
C# has finalizers (similar to destructors except that the runtime doesn't guarantee they'll be called), and they are specified as follows:
class C
{
~C()
{
// your code
}
public static void Main() {}
}
Currently, they override object.Finalize(), which is called during the GC process.
My switch statement works differently! Why?
C# does not support an explicit fall through for case blocks.
The following code is not legal and will not compile in C#: switch(x)
{
case 0:
// do something
case 1:
// do something in common with 0
default:
// do something in common with
//0, 1 and everything else
break;
}
To achieve the same effect in C#, the code must be modified
as shown below (notice how the control flows are explicit): class Test
{
public static void Main()
{
int x = 3;
switch(x)
{
case 0:
// do something
goto case 1;
case 1:
// do something in common with 0
goto default;
default:
// do something in common with 0, 1, and anything else
break;
}
}
}
How can I access the registry from C# code?
By using the Registry and RegistryKey classes in Microsoft.Win32, you can easily access the registry. The following is a sample that reads a key and displays its value:
using System;using Microsoft.Win32;
class regTest
{
public static void Main(String[] args)
{
RegistryKey regKey;
Object value;
regKey = Registry.LocalMachine;
regKey =
regKey.OpenSubKey("HARDWAREDESCRIPTIONSystemCentralProcessor ");
value = regKey.GetValue("VendorIdentifier");
Console.WriteLine("The central processor of this machine is: {0}.", value);
}
}
How can you sort the elements of the array in descending order?
By calling Sort() and then Reverse() methods.
How do you debug an ASP.NET Web application?
Attach the aspnet_wp.exe process to the DbgClr debugger.
How do you mark a method obsolete?
Assuming you've done a "using System;": [Obsolete]
public int Foo() {...}
or [Obsolete("This is a message describing why this method is obsolete")]
public int Foo() {...}
Note: The O in Obsolete is capitalized.
How is the DLL Hell problem solved in .NET?
Assembly versioning allows the application to specify not only the library it needs to run (which was available under Win32), but also the version of the assembly
What are the ways to deploy an assembly?
An MSI installer, a CAB archive, and XCOPY command.
C# Interview Questions and Answers 10
How do I convert a string to an int in C#?
Here's an example: using System;
class StringToInt
{
public static void Main()
{
String s = "105";
int x = Convert.ToInt32(s);
Console.WriteLine(x);
}
}
How do you directly call a native function exported from a DLL?
Here's a quick example of the DllImport attribute in action: using System.Runtime.InteropServices;
class C
{
[DllImport("user32.dll")]
public static extern int MessageBoxA(int h, string m, string c, int type);
public static int Main()
{
return MessageBoxA(0, "Hello World!", "Caption", 0);
}
}
This example shows the minimum requirements for declaring a C# method that is implemented in a native DLL. The method C.MessageBoxA() is declared with the static and external modifiers, and has the DllImport attribute, which tells the compiler that the implementation comes from the user32.dll, using the default name of MessageBoxA. For more information, look at the Platform Invoke tutorial in the documentation.
What is the .NET datatype that allows the retrieval of data by a unique key?
HashTable.
How do you specify a custom attribute for the entire assembly (rather than for a class)?
Global attributes must appear after any top-level using clauses and before the first type or namespace declarations. An example of this is as follows:
using System;
[assembly : MyAttributeClass]
class X {}
Note that in an IDE-created project, by convention, these attributes are placed in
AssemblyInfo.cs.
What is the difference between a struct and a class in C#?
From language spec:
The list of similarities between classes and structs is as follows. Longstructs can implement interfaces and can have the same kinds of members as classes. Structs differ from classes in several important ways; however, structs are value types rather than reference types, and inheritance is not supported for structs. Struct values are stored on the stack or in-line. Careful programmers can sometimes enhance performance through judicious use of structs. For example, the use of a struct rather than a class for a Point can make a large difference in the number of memory allocations performed at runtime. The program below creates and initializes an array of 100 points. With Point implemented as a class, 101 separate objects are instantiated-one for the array and one each for the 100 elements.
What is the difference between the Debug class and Trace class?
Documentation looks the same. Use Debug class for debug builds, use Trace class for both debug and release builds.
How can you overload a method?
Different parameter data types, different number of parameters, different order of parameters.
What debugging tools come with the .NET SDK?
CorDBG - command-line debugger, and DbgCLR - graphic debugger. Visual Studio .NET uses the DbgCLR. To use CorDbg, you must compile the original C# file using the /debug switch.
What does Dispose method do with the connection object?
Deletes it from the memory.
How do you generate documentation from the C# file commented properly with a command-line compiler?
Compile it with a /doc switch.
When you inherit a protected class-level variable, who is it available to?
Classes in the same namespace.
How can I get the ASCII code for a character in C#?
Casting the char to an int will give you the ASCII value: char c = 'f'; System.Console.WriteLine((int)c); or for a character in a string: System.Console.WriteLine((int)s[3]); The base class libraries also offer ways to do this with the Convert class or Encoding classes if you need a particular encoding.
Is there an equivalent to the instanceof operator in Visual J++?
C# has the is operator:
expr is type
Here's an example: using System;
class StringToInt
{
public static void Main()
{
String s = "105";
int x = Convert.ToInt32(s);
Console.WriteLine(x);
}
}
How do you directly call a native function exported from a DLL?
Here's a quick example of the DllImport attribute in action: using System.Runtime.InteropServices;
class C
{
[DllImport("user32.dll")]
public static extern int MessageBoxA(int h, string m, string c, int type);
public static int Main()
{
return MessageBoxA(0, "Hello World!", "Caption", 0);
}
}
This example shows the minimum requirements for declaring a C# method that is implemented in a native DLL. The method C.MessageBoxA() is declared with the static and external modifiers, and has the DllImport attribute, which tells the compiler that the implementation comes from the user32.dll, using the default name of MessageBoxA. For more information, look at the Platform Invoke tutorial in the documentation.
What is the .NET datatype that allows the retrieval of data by a unique key?
HashTable.
How do you specify a custom attribute for the entire assembly (rather than for a class)?
Global attributes must appear after any top-level using clauses and before the first type or namespace declarations. An example of this is as follows:
using System;
[assembly : MyAttributeClass]
class X {}
Note that in an IDE-created project, by convention, these attributes are placed in
AssemblyInfo.cs.
What is the difference between a struct and a class in C#?
From language spec:
The list of similarities between classes and structs is as follows. Longstructs can implement interfaces and can have the same kinds of members as classes. Structs differ from classes in several important ways; however, structs are value types rather than reference types, and inheritance is not supported for structs. Struct values are stored on the stack or in-line. Careful programmers can sometimes enhance performance through judicious use of structs. For example, the use of a struct rather than a class for a Point can make a large difference in the number of memory allocations performed at runtime. The program below creates and initializes an array of 100 points. With Point implemented as a class, 101 separate objects are instantiated-one for the array and one each for the 100 elements.
What is the difference between the Debug class and Trace class?
Documentation looks the same. Use Debug class for debug builds, use Trace class for both debug and release builds.
How can you overload a method?
Different parameter data types, different number of parameters, different order of parameters.
What debugging tools come with the .NET SDK?
CorDBG - command-line debugger, and DbgCLR - graphic debugger. Visual Studio .NET uses the DbgCLR. To use CorDbg, you must compile the original C# file using the /debug switch.
What does Dispose method do with the connection object?
Deletes it from the memory.
How do you generate documentation from the C# file commented properly with a command-line compiler?
Compile it with a /doc switch.
When you inherit a protected class-level variable, who is it available to?
Classes in the same namespace.
How can I get the ASCII code for a character in C#?
Casting the char to an int will give you the ASCII value: char c = 'f'; System.Console.WriteLine((int)c); or for a character in a string: System.Console.WriteLine((int)s[3]); The base class libraries also offer ways to do this with the Convert class or Encoding classes if you need a particular encoding.
Is there an equivalent to the instanceof operator in Visual J++?
C# has the is operator:
expr is type
C# Interview Questions and Answers 9
What is the wildcard character in SQL?
Let us say you want to query database with LIKE for all employees whose name starts with La. The wildcard character is %, the proper query with LIKE would involve La%.
What is the role of the DataReader class in ADO.NET connections?
It returns a read-only dataset from the data source when the command is executed.
What does the This window show in the debugger?
It points to the object that is pointed to by this reference. Object’s instance data is shown.
Describe the accessibility modifier protected internal?
It is available to derived classes and classes within the same Assembly (and naturally from the base class it is declared in).
What is an interface class?
It is an abstract class with public abstract methods all of which must be implemented in the inherited classes.
What is a multicast delegate?
It is a delegate that points to and eventually fires off several methods.
How does one compare strings in C#?
In the past, you had to call .ToString() on the strings when using the == or != operators to compare the strings' values. That will still work, but the C# compiler now automatically compares the values instead of the references when the == or != operators are used on string types. If you actually do want to compare references, it can be done as follows: if ((object) str1 == (object) str2) { ... } Here's an example showing how string compares work: using System;
public class StringTest
{
public static void Main(string[] args)
{
Object nullObj = null;
Object realObj = new StringTest();
int i = 10;
Console.WriteLine("Null Object is [" + nullObj + "]n" +
"Real Object is [" + realObj + "]n" +
"i is [" + i + "]n");
// Show string equality operators
string str1 = "foo";
string str2 = "bar";
string str3 = "bar";
Console.WriteLine("{0} == {1} ? {2}", str1, str2, str1 == str2 );
Console.WriteLine("{0} == {1} ? {2}", str2, str3, str2 == str3 );
}
}
Output: Null Object is []
Real Object is [StringTest]
i is [10]
foo == bar ? False
bar == bar ? True
What does assert() do?
In debug compilation, assert takes in a Boolean condition as a parameter, and shows the error dialog if the condition is false. The program proceeds without any interruption if the condition is true.
How do I get deterministic finalization in C#?
In a garbage collected environment, it's impossible to get true determinism. However, a design pattern that we recommend is implementing IDisposable on any class that contains a critical resource. Whenever this class is consumed, it may be placed in a using statement, as shown in the following example:
using(FileStream myFile = File.Open(@"c:temptest.txt",
FileMode.Open))
{
int fileOffset = 0;
while(fileOffset < myFile.Length)
{
Console.Write((char)myFile.ReadByte());
fileOffset++;
}
}
When myFile leaves the lexical scope of the using, its dispose method will be called.
How can I get around scope problems in a try/catch?
If you try to instantiate the class inside the try, it'll be out of scope when you try to access it from the catch block. A way to get around this is to do the following: Connection conn = null;
try
{
conn = new Connection();
conn.Open();
}
finally
{
if (conn != null) conn.Close();
}
By setting it to null before the try block, you avoid getting the CS0165 error (Use of possibly unassigned local variable 'conn').
Why do I get an error (CS1006) when trying to declare a method without specifying a return type?
If you leave off the return type on a method declaration, the compiler thinks you are trying to declare a constructor. So if you are trying to declare a method that returns nothing, use void. The following is an example: // This results in a CS1006 error public static staticMethod (mainStatic obj) // This will work as wanted public static void staticMethod (mainStatic obj)
Let us say you want to query database with LIKE for all employees whose name starts with La. The wildcard character is %, the proper query with LIKE would involve La%.
What is the role of the DataReader class in ADO.NET connections?
It returns a read-only dataset from the data source when the command is executed.
What does the This window show in the debugger?
It points to the object that is pointed to by this reference. Object’s instance data is shown.
Describe the accessibility modifier protected internal?
It is available to derived classes and classes within the same Assembly (and naturally from the base class it is declared in).
What is an interface class?
It is an abstract class with public abstract methods all of which must be implemented in the inherited classes.
What is a multicast delegate?
It is a delegate that points to and eventually fires off several methods.
How does one compare strings in C#?
In the past, you had to call .ToString() on the strings when using the == or != operators to compare the strings' values. That will still work, but the C# compiler now automatically compares the values instead of the references when the == or != operators are used on string types. If you actually do want to compare references, it can be done as follows: if ((object) str1 == (object) str2) { ... } Here's an example showing how string compares work: using System;
public class StringTest
{
public static void Main(string[] args)
{
Object nullObj = null;
Object realObj = new StringTest();
int i = 10;
Console.WriteLine("Null Object is [" + nullObj + "]n" +
"Real Object is [" + realObj + "]n" +
"i is [" + i + "]n");
// Show string equality operators
string str1 = "foo";
string str2 = "bar";
string str3 = "bar";
Console.WriteLine("{0} == {1} ? {2}", str1, str2, str1 == str2 );
Console.WriteLine("{0} == {1} ? {2}", str2, str3, str2 == str3 );
}
}
Output: Null Object is []
Real Object is [StringTest]
i is [10]
foo == bar ? False
bar == bar ? True
What does assert() do?
In debug compilation, assert takes in a Boolean condition as a parameter, and shows the error dialog if the condition is false. The program proceeds without any interruption if the condition is true.
How do I get deterministic finalization in C#?
In a garbage collected environment, it's impossible to get true determinism. However, a design pattern that we recommend is implementing IDisposable on any class that contains a critical resource. Whenever this class is consumed, it may be placed in a using statement, as shown in the following example:
using(FileStream myFile = File.Open(@"c:temptest.txt",
FileMode.Open))
{
int fileOffset = 0;
while(fileOffset < myFile.Length)
{
Console.Write((char)myFile.ReadByte());
fileOffset++;
}
}
When myFile leaves the lexical scope of the using, its dispose method will be called.
How can I get around scope problems in a try/catch?
If you try to instantiate the class inside the try, it'll be out of scope when you try to access it from the catch block. A way to get around this is to do the following: Connection conn = null;
try
{
conn = new Connection();
conn.Open();
}
finally
{
if (conn != null) conn.Close();
}
By setting it to null before the try block, you avoid getting the CS0165 error (Use of possibly unassigned local variable 'conn').
Why do I get an error (CS1006) when trying to declare a method without specifying a return type?
If you leave off the return type on a method declaration, the compiler thinks you are trying to declare a constructor. So if you are trying to declare a method that returns nothing, use void. The following is an example: // This results in a CS1006 error public static staticMethod (mainStatic obj) // This will work as wanted public static void staticMethod (mainStatic obj)
C# Interview Questions and Answers8
Can I define a type that is an alias of another type (like typedef in C++)?
Not exactly. You can create an alias within a single file with the "using" directive: using System; using Integer = System.Int32; // alias
But you can't create a true alias, one that extends beyond the file in which it is declared. Refer to the C# spec for more info on the 'using' statement's scope.
Is it possible to have different access modifiers on the get/set methods of a property?
No. The access modifier on a property applies to both its get and set accessors. What you need to do if you want them to be different is make the property read-only (by only providing a get accessor) and create a private/internal set method that is separate from the property.
Is it possible to have a static indexer in C#?
No. Static indexers are not allowed in C#.
Does C# support #define for defining global constants?
No. If you want to get something that works like the following C code:
#define A 1
use the following C# code: class MyConstants
{
public const int A = 1;
}
Then you use MyConstants.A where you would otherwise use the A macro.
Using MyConstants.A has the same generated code as using the literal 1.
Does C# support templates?
No. However, there are plans for C# to support a type of template known as a generic. These generic types have similar syntax but are instantiated at run time as opposed to compile time. You can read more about them here.
Does C# support parameterized properties?
No. C# does, however, support the concept of an indexer from language spec. An indexer is a member that enables an object to be indexed in the same way as an array. Whereas properties enable field-like access, indexers enable array-like access. As an example, consider the Stack class presented earlier. The designer of this class may want to expose array-like access so that it is possible to inspect or alter the items on the stack without performing unnecessary Push and Pop operations. That is, Stack is implemented as a linked list, but it also provides the convenience of array access.
Indexer declarations are similar to property declarations, with the main differences being that indexers are nameless (the name used in the declaration is this, since this is being indexed) and that indexers include indexing parameters. The indexing parameters are provided between square brackets.
Does C# support C type macros?
No. C# does not have macros. Keep in mind that what some of the predefined C macros (for example, __LINE__ and __FILE__) give you can also be found in .NET classes like System.Diagnostics (for example, StackTrace and StackFrame), but they'll only work on debug builds.
Can you store multiple data types in System.Array?
No.
Is it possible to inline assembly or IL in C# code?
No.
Can you declare the override method static while the original method is non-static?
No, you cannot, the signature of the virtual method must remain the same, only the keyword virtual is changed to keyword override
Does C# support multiple inheritance?
No, use interfaces instead.
Can multiple catch blocks be executed?
No, once the proper catch code fires off, the control is transferred to the finally block (if there are any), and then whatever follows the finally block.
Can you override private virtual methods?
No, moreover, you cannot access private methods in inherited classes, have to be protected in the base class to allow any sort of access.
What is a pre-requisite for connection pooling?
Multiple processes must agree that they will share the same connection, where every parameter is the same,
What is the data provider name to connect to Access database?
Microsoft.Access.
Why does my Windows application pop up a console window every time I run it?
Make sure that the target type set in the project properties setting is set to Windows Application, and not Console Application. If you're using the command line, compile with /target:winexe & not target:exe.
Not exactly. You can create an alias within a single file with the "using" directive: using System; using Integer = System.Int32; // alias
But you can't create a true alias, one that extends beyond the file in which it is declared. Refer to the C# spec for more info on the 'using' statement's scope.
Is it possible to have different access modifiers on the get/set methods of a property?
No. The access modifier on a property applies to both its get and set accessors. What you need to do if you want them to be different is make the property read-only (by only providing a get accessor) and create a private/internal set method that is separate from the property.
Is it possible to have a static indexer in C#?
No. Static indexers are not allowed in C#.
Does C# support #define for defining global constants?
No. If you want to get something that works like the following C code:
#define A 1
use the following C# code: class MyConstants
{
public const int A = 1;
}
Then you use MyConstants.A where you would otherwise use the A macro.
Using MyConstants.A has the same generated code as using the literal 1.
Does C# support templates?
No. However, there are plans for C# to support a type of template known as a generic. These generic types have similar syntax but are instantiated at run time as opposed to compile time. You can read more about them here.
Does C# support parameterized properties?
No. C# does, however, support the concept of an indexer from language spec. An indexer is a member that enables an object to be indexed in the same way as an array. Whereas properties enable field-like access, indexers enable array-like access. As an example, consider the Stack class presented earlier. The designer of this class may want to expose array-like access so that it is possible to inspect or alter the items on the stack without performing unnecessary Push and Pop operations. That is, Stack is implemented as a linked list, but it also provides the convenience of array access.
Indexer declarations are similar to property declarations, with the main differences being that indexers are nameless (the name used in the declaration is this, since this is being indexed) and that indexers include indexing parameters. The indexing parameters are provided between square brackets.
Does C# support C type macros?
No. C# does not have macros. Keep in mind that what some of the predefined C macros (for example, __LINE__ and __FILE__) give you can also be found in .NET classes like System.Diagnostics (for example, StackTrace and StackFrame), but they'll only work on debug builds.
Can you store multiple data types in System.Array?
No.
Is it possible to inline assembly or IL in C# code?
No.
Can you declare the override method static while the original method is non-static?
No, you cannot, the signature of the virtual method must remain the same, only the keyword virtual is changed to keyword override
Does C# support multiple inheritance?
No, use interfaces instead.
Can multiple catch blocks be executed?
No, once the proper catch code fires off, the control is transferred to the finally block (if there are any), and then whatever follows the finally block.
Can you override private virtual methods?
No, moreover, you cannot access private methods in inherited classes, have to be protected in the base class to allow any sort of access.
What is a pre-requisite for connection pooling?
Multiple processes must agree that they will share the same connection, where every parameter is the same,
What is the data provider name to connect to Access database?
Microsoft.Access.
Why does my Windows application pop up a console window every time I run it?
Make sure that the target type set in the project properties setting is set to Windows Application, and not Console Application. If you're using the command line, compile with /target:winexe & not target:exe.
C# Interview Questions and Answers7
From a versioning perspective, what are the drawbacks of extending an interface as opposed to extending a class?
With regard to versioning, interfaces are less flexible than classes. With a class, you can ship version 1 and then, in version 2, decide to add another method. As long as the method is not abstract (i.e., as long as you provide a default implementation of the method), any existing derived classes continue to function with no changes. Because interfaces do not support implementation inheritance, this same pattern does not hold for interfaces. Adding a method to an interface is like adding an abstract method to a base class--any class that implements the interface will break, because the class doesn't implement the new interface method.
Which one is trusted and which one is untrusted?
Windows Authentication is trusted because the username and password are checked with the Active Directory, the SQL Server authentication is untrusted, since SQL Server is the only verifier participating in the transaction
What namespaces are necessary to create a localized application?
System.Globalization, System.Resources.
Does Console.WriteLine() stop printing when it reaches a NULL character within a string?
Strings are not null terminated in the runtime, so embedded nulls are allowed. Console.WriteLine() and all similar methods continue until the end of the string.
What is the advantage of using System.Text.StringBuilder over System.String?
StringBuilder is more efficient in the cases, where a lot of manipulation is done to the text. Strings are immutable, so each time it is being operated on, a new instance is created.
What are advantages and disadvantages of Microsoft-provided data provider classes in ADO.NET?
SQLServer.NET data provider is high-speed and robust, but requires SQL Server license purchased from Microsoft. OLE-DB.NET is universal for accessing other sources, like Oracle, DB2, Microsoft Access and Informix, but it is a .NET layer on top of OLE layer, so not the fastest thing in the world. ODBC.NET is a deprecated layer provided for backward compatibility to ODBC engines.
Why do I get a security exception when I try to run my C# app?
Some security exceptions are thrown if you are working on a network share. There are some parts of the frameworks that will not run if being run off a share (roaming profile, mapped drives, etc.). To see if this is what's happening, just move the executable over to your local drive and see if it runs without the exceptions. One of the common exceptions thrown under these conditions is
System.Security.SecurityException.
To get around this, you can change your security policy for the intranet zone, code group 1.2, (the zone that running off shared folders falls into) by using the caspol.exe tool.
Is there any sample C# code for simple threading?
Some sample code follows: using System;
using System.Threading;
class ThreadTest
{
public void runme()
{
Console.WriteLine("Runme Called");
}
public static void Main(String[] args)
{
ThreadTest b = new ThreadTest();
Thread t = new Thread(new ThreadStart(b.runme));
t.Start();
}
}
What is the difference between // comments, /* */ comments and /// comments?
Single-line, multi-line and XML documentation comments.
What is the difference between and XML documentation tag?
Single line code example and multiple-line code example.
Explain the three services model (three-tier application). Presentation (UI), business (logic and underlying code) and data (from storage or other sources).
What are three test cases you should go through in unit testing? Positive test cases (correct data, correct output), negative test cases (broken or missing data, proper handling), exception test cases (exceptions are thrown and caught properly).
How do you inherit from a class in C#?
Place a colon and then the name of the base class. Notice that it is double colon in C++.
How do I port "synchronized" functions from Visual J++ to C#?
Original Visual J++ code: public synchronized void Run()
{
// function body
}
Ported C# code: class C
{
public void Run()
{
lock(this)
{
// function body
}
}
public static void Main() {}
}
With regard to versioning, interfaces are less flexible than classes. With a class, you can ship version 1 and then, in version 2, decide to add another method. As long as the method is not abstract (i.e., as long as you provide a default implementation of the method), any existing derived classes continue to function with no changes. Because interfaces do not support implementation inheritance, this same pattern does not hold for interfaces. Adding a method to an interface is like adding an abstract method to a base class--any class that implements the interface will break, because the class doesn't implement the new interface method.
Which one is trusted and which one is untrusted?
Windows Authentication is trusted because the username and password are checked with the Active Directory, the SQL Server authentication is untrusted, since SQL Server is the only verifier participating in the transaction
What namespaces are necessary to create a localized application?
System.Globalization, System.Resources.
Does Console.WriteLine() stop printing when it reaches a NULL character within a string?
Strings are not null terminated in the runtime, so embedded nulls are allowed. Console.WriteLine() and all similar methods continue until the end of the string.
What is the advantage of using System.Text.StringBuilder over System.String?
StringBuilder is more efficient in the cases, where a lot of manipulation is done to the text. Strings are immutable, so each time it is being operated on, a new instance is created.
What are advantages and disadvantages of Microsoft-provided data provider classes in ADO.NET?
SQLServer.NET data provider is high-speed and robust, but requires SQL Server license purchased from Microsoft. OLE-DB.NET is universal for accessing other sources, like Oracle, DB2, Microsoft Access and Informix, but it is a .NET layer on top of OLE layer, so not the fastest thing in the world. ODBC.NET is a deprecated layer provided for backward compatibility to ODBC engines.
Why do I get a security exception when I try to run my C# app?
Some security exceptions are thrown if you are working on a network share. There are some parts of the frameworks that will not run if being run off a share (roaming profile, mapped drives, etc.). To see if this is what's happening, just move the executable over to your local drive and see if it runs without the exceptions. One of the common exceptions thrown under these conditions is
System.Security.SecurityException.
To get around this, you can change your security policy for the intranet zone, code group 1.2, (the zone that running off shared folders falls into) by using the caspol.exe tool.
Is there any sample C# code for simple threading?
Some sample code follows: using System;
using System.Threading;
class ThreadTest
{
public void runme()
{
Console.WriteLine("Runme Called");
}
public static void Main(String[] args)
{
ThreadTest b = new ThreadTest();
Thread t = new Thread(new ThreadStart(b.runme));
t.Start();
}
}
What is the difference between // comments, /* */ comments and /// comments?
Single-line, multi-line and XML documentation comments.
What is the difference between and XML documentation tag?
Single line code example and multiple-line code example.
Explain the three services model (three-tier application). Presentation (UI), business (logic and underlying code) and data (from storage or other sources).
What are three test cases you should go through in unit testing? Positive test cases (correct data, correct output), negative test cases (broken or missing data, proper handling), exception test cases (exceptions are thrown and caught properly).
How do you inherit from a class in C#?
Place a colon and then the name of the base class. Notice that it is double colon in C++.
How do I port "synchronized" functions from Visual J++ to C#?
Original Visual J++ code: public synchronized void Run()
{
// function body
}
Ported C# code: class C
{
public void Run()
{
lock(this)
{
// function body
}
}
public static void Main() {}
}
C# Interview Questions and Answers 6
How can I create a process that is running a supplied native executable (e.g., cmd.exe)?
The following code should run the executable and wait for it to exit before
continuing: using System;
using System.Diagnostics;
public class ProcessTest {
public static void Main(string[] args) {
Process p = Process.Start(args[0]);
p.WaitForExit();
Console.WriteLine(args[0] + " exited.");
}
}
Remember to add a reference to System.Diagnostics.dll when you compile.
What is the difference between the System.Array.CopyTo() and System.Array.Clone()?
The first one performs a deep copy of the array, the second one is shallow.
How do I declare inout arguments in C#?
The equivalent of inout in C# is ref. , as shown in the following
example: public void MyMethod (ref String str1, out String str2)
{
...
}
When calling the method, it would be called like this: String s1;
String s2;
s1 = "Hello";
MyMethod(ref s1, out s2);
Console.WriteLine(s1);
Console.WriteLine(s2);
Notice that you need to specify ref when declaring the function and calling it.
Is there a way of specifying which block or loop to break out of when working with nested loops?
The easiest way is to use goto: using System;
class BreakExample
{
public static void Main(String[] args)
{
for(int i=0; i<3; i++)
{
Console.WriteLine("Pass {0}: ", i);
for( int j=0 ; j<100 ; j++ )
{
if ( j == 10) goto done;
Console.WriteLine("{0} ", j);
}
Console.WriteLine("This will not print");
}
done:
Console.WriteLine("Loops complete.");
}
}
What is the difference between const and static read-only?
The difference is that static read-only can be modified by the containing class, but const can never be modified and must be initialized to a compile time constant. To expand on the static read-only case a bit, the containing class can only modify it: -- in the variable declaration (through a variable initializer).
-- in the static constructor (instance constructors if it's not static).
What does the parameter Initial Catalog define inside Connection String?
The database name to connect to.
What is the difference between System.String and System.StringBuilder classes?
System.String is immutable; System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed.
What is the top .NET class that everything is derived from?
System.Object.
Can you allow class to be inherited, but prevent the method from being over-ridden?
Yes, just leave the class public and make the method sealed
Can you change the value of a variable while debugging a C# application?
Yes, if you are debugging via Visual Studio.NET, just go to Immediate window.
Are private class-level variables inherited?
Yes, but they are not accessible, so looking at it you can honestly say that they are not inherited. But they are.
Can you inherit multiple interfaces?
Yes. .NET does support multiple interfaces.
The following code should run the executable and wait for it to exit before
continuing: using System;
using System.Diagnostics;
public class ProcessTest {
public static void Main(string[] args) {
Process p = Process.Start(args[0]);
p.WaitForExit();
Console.WriteLine(args[0] + " exited.");
}
}
Remember to add a reference to System.Diagnostics.dll when you compile.
What is the difference between the System.Array.CopyTo() and System.Array.Clone()?
The first one performs a deep copy of the array, the second one is shallow.
How do I declare inout arguments in C#?
The equivalent of inout in C# is ref. , as shown in the following
example: public void MyMethod (ref String str1, out String str2)
{
...
}
When calling the method, it would be called like this: String s1;
String s2;
s1 = "Hello";
MyMethod(ref s1, out s2);
Console.WriteLine(s1);
Console.WriteLine(s2);
Notice that you need to specify ref when declaring the function and calling it.
Is there a way of specifying which block or loop to break out of when working with nested loops?
The easiest way is to use goto: using System;
class BreakExample
{
public static void Main(String[] args)
{
for(int i=0; i<3; i++)
{
Console.WriteLine("Pass {0}: ", i);
for( int j=0 ; j<100 ; j++ )
{
if ( j == 10) goto done;
Console.WriteLine("{0} ", j);
}
Console.WriteLine("This will not print");
}
done:
Console.WriteLine("Loops complete.");
}
}
What is the difference between const and static read-only?
The difference is that static read-only can be modified by the containing class, but const can never be modified and must be initialized to a compile time constant. To expand on the static read-only case a bit, the containing class can only modify it: -- in the variable declaration (through a variable initializer).
-- in the static constructor (instance constructors if it's not static).
What does the parameter Initial Catalog define inside Connection String?
The database name to connect to.
What is the difference between System.String and System.StringBuilder classes?
System.String is immutable; System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed.
What is the top .NET class that everything is derived from?
System.Object.
Can you allow class to be inherited, but prevent the method from being over-ridden?
Yes, just leave the class public and make the method sealed
Can you change the value of a variable while debugging a C# application?
Yes, if you are debugging via Visual Studio.NET, just go to Immediate window.
Are private class-level variables inherited?
Yes, but they are not accessible, so looking at it you can honestly say that they are not inherited. But they are.
Can you inherit multiple interfaces?
Yes. .NET does support multiple interfaces.
C# Interview Questions and Answers 5
How do I create a multi language, multi file assembly?
Unfortunately, this is currently not supported in the IDE. To do this from the command line, you must compile your projects into netmodules (/target:module on the C# compiler), and then use the command line tool al.exe (alink) to link these netmodules together.
C# provides a default constructor for me. I write a constructor that takes a string as a parameter, but want to keep the no parameter one. How many constructors should I write?
Two. Once you write at least one constructor, C# cancels the freebie constructor, and now you have to write one yourself, even if there is no implementation in
What is the equivalent to regsvr32 and regsvr32 /u a file in .NET development?
Try using RegAsm.exe. The general syntax would be: RegAsm. A good description of RegAsm and its associated switches is located in the .NET SDK docs. Just search on "Assembly Registration Tool".Explain ACID rule of thumb for transactions.
Transaction must be Atomic (it is one unit of work and does not dependent on previous and following transactions), Consistent (data is either committed or roll back, no in-between case where something has been updated and something hasnot), Isolated (no transaction sees the intermediate results of the current transaction), Durable (the values persist if the data had been committed even if the system crashes right after).
Where is the output of TextWriterTraceListener redirected?
To the Console or a text file depending on the parameter passed to the constructor.
How do I create a multilanguage, single-file assembly?
This is currently not supported by Visual Studio .NET.
Why cannot you specify the accessibility modifier for methods inside the interface?
They all must be public. Therefore, to prevent you from getting the false impression that you have any freedom of choice, you are not allowed to specify any accessibility, it is public by default.
Is it possible to restrict the scope of a field/method of a class to the classes in the same namespace?
There is no way to restrict to a namespace. Namespaces are never units of protection. But if you're using assemblies, you can use the 'internal' access modifier to restrict access to only within the assembly.
Why do I get a syntax error when trying to declare a variable called checked?
The word checked is a keyword in C#.
Why are there five tracing levels in System.Diagnostics.TraceSwitcher?
The tracing dumps can be quite verbose and for some applications that are constantly running you run the risk of overloading the machine and the hard drive there. Five levels range from None to Verbose, allowing to fine-tune the tracing activities.
What is the syntax for calling an overloaded constructor within a constructor (this() and constructorname() does not compile)?
The syntax for calling another constructor is as follows:
class B
{
B(int i)
{ }
}
class C : B
{
C() : base(5) // call base constructor B(5)
{ }
C(int i) : this() // call C()
{ }
public static void Main() {}
}
Why do I get a "CS5001: does not have an entry point defined" error when compiling?
The most common problem is that you used a lowercase 'm' when defining the Main method. The correct way to implement the entry point is as follows:
class test
{
static void Main(string[] args) {}
}
What does the keyword virtual mean in the method definition?
The method can be over-ridden.
What optimizations does the C# compiler perform when you use the /optimize+ compiler option?
The following is a response from a developer on the C# compiler team:
We get rid of unused locals (i.e., locals that are never read, even if assigned).
We get rid of unreachable code.
We get rid of try-catch w/ an empty try.
We get rid of try-finally w/ an empty try (convert to normal code...).
We get rid of try-finally w/ an empty finally (convert to normal code...).
We optimize branches over branches:
gotoif A, lab1
goto lab2:
lab1:
turns into: gotoif !A, lab2
lab1:
We optimize branches to ret, branches to next instruction, and branches to branches.
Unfortunately, this is currently not supported in the IDE. To do this from the command line, you must compile your projects into netmodules (/target:module on the C# compiler), and then use the command line tool al.exe (alink) to link these netmodules together.
C# provides a default constructor for me. I write a constructor that takes a string as a parameter, but want to keep the no parameter one. How many constructors should I write?
Two. Once you write at least one constructor, C# cancels the freebie constructor, and now you have to write one yourself, even if there is no implementation in
What is the equivalent to regsvr32 and regsvr32 /u a file in .NET development?
Try using RegAsm.exe. The general syntax would be: RegAsm. A good description of RegAsm and its associated switches is located in the .NET SDK docs. Just search on "Assembly Registration Tool".Explain ACID rule of thumb for transactions.
Transaction must be Atomic (it is one unit of work and does not dependent on previous and following transactions), Consistent (data is either committed or roll back, no in-between case where something has been updated and something hasnot), Isolated (no transaction sees the intermediate results of the current transaction), Durable (the values persist if the data had been committed even if the system crashes right after).
Where is the output of TextWriterTraceListener redirected?
To the Console or a text file depending on the parameter passed to the constructor.
How do I create a multilanguage, single-file assembly?
This is currently not supported by Visual Studio .NET.
Why cannot you specify the accessibility modifier for methods inside the interface?
They all must be public. Therefore, to prevent you from getting the false impression that you have any freedom of choice, you are not allowed to specify any accessibility, it is public by default.
Is it possible to restrict the scope of a field/method of a class to the classes in the same namespace?
There is no way to restrict to a namespace. Namespaces are never units of protection. But if you're using assemblies, you can use the 'internal' access modifier to restrict access to only within the assembly.
Why do I get a syntax error when trying to declare a variable called checked?
The word checked is a keyword in C#.
Why are there five tracing levels in System.Diagnostics.TraceSwitcher?
The tracing dumps can be quite verbose and for some applications that are constantly running you run the risk of overloading the machine and the hard drive there. Five levels range from None to Verbose, allowing to fine-tune the tracing activities.
What is the syntax for calling an overloaded constructor within a constructor (this() and constructorname() does not compile)?
The syntax for calling another constructor is as follows:
class B
{
B(int i)
{ }
}
class C : B
{
C() : base(5) // call base constructor B(5)
{ }
C(int i) : this() // call C()
{ }
public static void Main() {}
}
Why do I get a "CS5001: does not have an entry point defined" error when compiling?
The most common problem is that you used a lowercase 'm' when defining the Main method. The correct way to implement the entry point is as follows:
class test
{
static void Main(string[] args) {}
}
What does the keyword virtual mean in the method definition?
The method can be over-ridden.
What optimizations does the C# compiler perform when you use the /optimize+ compiler option?
The following is a response from a developer on the C# compiler team:
We get rid of unused locals (i.e., locals that are never read, even if assigned).
We get rid of unreachable code.
We get rid of try-catch w/ an empty try.
We get rid of try-finally w/ an empty try (convert to normal code...).
We get rid of try-finally w/ an empty finally (convert to normal code...).
We optimize branches over branches:
gotoif A, lab1
goto lab2:
lab1:
turns into: gotoif !A, lab2
lab1:
We optimize branches to ret, branches to next instruction, and branches to branches.
C# Interview Questions and Answers 4
Is there regular expression (regex) support available to C# developers?
Yes. The .NET class libraries provide support for regular expressions. Look at the documentation for the System.Text.RegularExpressions namespace.
Is there a way to force garbage collection?
Yes. Set all references to null and then call System.GC.Collect(). If you need to have some objects destructed, and System.GC.Collect() doesn't seem to be doing it for you, you can force finalizers to be run by setting all the references to the object to null and then calling System.GC.RunFinalizers().
Does C# support properties of array types?
Yes. Here's a simple example: using System;
class Class1
{
private string[] MyField;
public string[] MyProperty
{
get { return MyField; }
set { MyField = value; }
}
}
class MainClass
{
public static int Main(string[] args)
{
Class1 c = new Class1();
string[] arr = new string[] {"apple", "banana"};
c.MyProperty = arr;
Console.WriteLine(c.MyProperty[0]); // "apple"
return 0;
}
}
What connections does Microsoft SQL Server support?
Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft SQL Server username and passwords)
What is a satellite assembly?
When you write a multilingual or multi-cultural application in .NET, and want to distribute the core application separately from the localized modules, the localized assemblies that modify the core application are called satellite assemblies.
How is method overriding different from overloading?
When overriding, you change the method behavior for a derived class. Overloading simply involves having a method with the same name within the class.
When do you absolutely have to declare a class as abstract (as opposed to free-willed educated choice or decision based on UML diagram)?
When at least one of the methods in the class is abstract. When the class itself is inherited from an abstract class, but not all base abstract methods have been over-ridden.
Why would you use untrusted verification?
Web Services might use it, as well as non-Windows applications.
What is the implicit name of the parameter that gets passed into the class set method?
Value, and its datatype depends on whatever variable we are changing.
How do I register my code for use by classic COM clients?
Use the regasm.exe utility to generate a type library (if needed) and the necessary entries in the Windows Registry to make a class available to classic COM clients. Once a class is registered in the Windows Registry with regasm.exe, a COM client can use the class as though it were a COM class.
How do I do implement a trace and assert?
Use a conditional attribute on the method, as shown below:
class Debug
{
[conditional("TRACE")]
public void Trace(string s)
{
Console.WriteLine(s);
}
}
class MyClass
{
public static void Main()
{
Debug.Trace("hello");
}
}
In this example, the call to Debug.Trace() is made only if the preprocessor symbol TRACE is defined at the call site. You can define preprocessor symbols on the command line by using the /D switch. The restriction on conditional methods is that they must have void return type.
Yes. The .NET class libraries provide support for regular expressions. Look at the documentation for the System.Text.RegularExpressions namespace.
Is there a way to force garbage collection?
Yes. Set all references to null and then call System.GC.Collect(). If you need to have some objects destructed, and System.GC.Collect() doesn't seem to be doing it for you, you can force finalizers to be run by setting all the references to the object to null and then calling System.GC.RunFinalizers().
Does C# support properties of array types?
Yes. Here's a simple example: using System;
class Class1
{
private string[] MyField;
public string[] MyProperty
{
get { return MyField; }
set { MyField = value; }
}
}
class MainClass
{
public static int Main(string[] args)
{
Class1 c = new Class1();
string[] arr = new string[] {"apple", "banana"};
c.MyProperty = arr;
Console.WriteLine(c.MyProperty[0]); // "apple"
return 0;
}
}
What connections does Microsoft SQL Server support?
Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft SQL Server username and passwords)
What is a satellite assembly?
When you write a multilingual or multi-cultural application in .NET, and want to distribute the core application separately from the localized modules, the localized assemblies that modify the core application are called satellite assemblies.
How is method overriding different from overloading?
When overriding, you change the method behavior for a derived class. Overloading simply involves having a method with the same name within the class.
When do you absolutely have to declare a class as abstract (as opposed to free-willed educated choice or decision based on UML diagram)?
When at least one of the methods in the class is abstract. When the class itself is inherited from an abstract class, but not all base abstract methods have been over-ridden.
Why would you use untrusted verification?
Web Services might use it, as well as non-Windows applications.
What is the implicit name of the parameter that gets passed into the class set method?
Value, and its datatype depends on whatever variable we are changing.
How do I register my code for use by classic COM clients?
Use the regasm.exe utility to generate a type library (if needed) and the necessary entries in the Windows Registry to make a class available to classic COM clients. Once a class is registered in the Windows Registry with regasm.exe, a COM client can use the class as though it were a COM class.
How do I do implement a trace and assert?
Use a conditional attribute on the method, as shown below:
class Debug
{
[conditional("TRACE")]
public void Trace(string s)
{
Console.WriteLine(s);
}
}
class MyClass
{
public static void Main()
{
Debug.Trace("hello");
}
}
In this example, the call to Debug.Trace() is made only if the preprocessor symbol TRACE is defined at the call site. You can define preprocessor symbols on the command line by using the /D switch. The restriction on conditional methods is that they must have void return type.
C Interview Questions 3
So let’s say I have an application that uses MyApp.dll assembly, version 1.0.0.0. There is a security bug in that assembly, and I publish the patch, issuing it under name MyApp.dll 1.1.0.0. How do I tell the client applications that are already installed to start using this new MyApp.dll?
Use publisher policy. To configure a publisher policy, use the publisher policy configuration file, which uses a format similar app .config file. But unlike the app .config file, a publisher policy file needs to be compiled into an assembly and placed in the GAC.
What is delay signing?
Delay signing allows you to place a shared assembly in the GAC by signing the assembly with just the public key. This allows the assembly to be signed with the private key at a later stage, when the development process is complete and the component or assembly is ready to be deployed. This process enables developers to work with shared assemblies as if they were strongly named, and it secures the private key of the signature from being accessed at different stages of development.
Is there an equivalent of exit() for quitting a C# .NET application?
Yes, you can use System.Environment.Exit(int exitCode) to exit the application or Application.Exit() if it's a Windows Forms app.
Can you prevent your class from being inherited and becoming a base class for some other classes?
Yes, that is what keyword sealed in the class definition is for. The developer trying to derive from your class will get a message: cannot inherit from Sealed class WhateverBaseClassName. It is the same concept as final class in Java.
Is XML case-sensitive?
Yes, so and are different elements.
If a base class has a bunch of overloaded constructors, and an inherited class has another bunch of overloaded constructors, can you enforce a call from an inherited constructor to an arbitrary base constructor?
Yes, just place a colon, and then keyword base (parameter list to invoke the appropriate constructor) in the overloaded constructor definition inside the inherited class.
I was trying to use an "out int" parameter in one of my functions. How should I declare the variable that I am passing to it?
You should declare the variable as an int, but when you pass it in you must specify it as 'out', like the following:
int i;
foo(out i);
where foo is declared as follows:
[return-type] foo(out int o) { }
How do I make a DLL in C#?
You need to use the /target:library compiler option.
How do I simulate optional parameters to COM calls?
You must use the Missing class and pass Missing.Value (in System.Reflection) for any values that have optional parameters.
Will finally block get executed if the exception had not occurred?
Yes.
What is the C# equivalent of C++ catch (…), which was a catch-all statement for any possible exception? Does C# support try-catch-finally blocks?
Yes. Try-catch-finally blocks are supported by the C# compiler. Here's an example of a try-catch-finally block: using System;
public class TryTest
{
static void Main()
{
try
{
Console.WriteLine("In Try block");
throw new ArgumentException();
}
catch(ArgumentException n1)
{
Console.WriteLine("Catch Block");
}
finally
{
Console.WriteLine("Finally Block");
}
}
}
Output: In Try Block
Catch Block
Finally Block
If I return out of a try/finally in C#, does the code in the finally-clause run? Yes. The code in the finally always runs. If you return out of the try block, or even if you do a "goto" out of the try, the finally block always runs, as shown in the following
example: using System;
class main
{
public static void Main()
{
try
{
Console.WriteLine("In Try block");
return;
}
finally
{
Console.WriteLine("In Finally block");
}
}
}
Both "In Try block" and "In Finally block" will be displayed. Whether the return is in the try block or after the try-finally block, performance is not affected either way. The compiler treats it as if the return were outside the try block anyway. If it's a return without an expression (as it is above), the IL emitted is identical whether the return is inside or outside of the try. If the return has an expression, there's an extra store/load of the value of the expression (since it has to be computed within the try block).
Use publisher policy. To configure a publisher policy, use the publisher policy configuration file, which uses a format similar app .config file. But unlike the app .config file, a publisher policy file needs to be compiled into an assembly and placed in the GAC.
What is delay signing?
Delay signing allows you to place a shared assembly in the GAC by signing the assembly with just the public key. This allows the assembly to be signed with the private key at a later stage, when the development process is complete and the component or assembly is ready to be deployed. This process enables developers to work with shared assemblies as if they were strongly named, and it secures the private key of the signature from being accessed at different stages of development.
Is there an equivalent of exit() for quitting a C# .NET application?
Yes, you can use System.Environment.Exit(int exitCode) to exit the application or Application.Exit() if it's a Windows Forms app.
Can you prevent your class from being inherited and becoming a base class for some other classes?
Yes, that is what keyword sealed in the class definition is for. The developer trying to derive from your class will get a message: cannot inherit from Sealed class WhateverBaseClassName. It is the same concept as final class in Java.
Is XML case-sensitive?
Yes, so and are different elements.
If a base class has a bunch of overloaded constructors, and an inherited class has another bunch of overloaded constructors, can you enforce a call from an inherited constructor to an arbitrary base constructor?
Yes, just place a colon, and then keyword base (parameter list to invoke the appropriate constructor) in the overloaded constructor definition inside the inherited class.
I was trying to use an "out int" parameter in one of my functions. How should I declare the variable that I am passing to it?
You should declare the variable as an int, but when you pass it in you must specify it as 'out', like the following:
int i;
foo(out i);
where foo is declared as follows:
[return-type] foo(out int o) { }
How do I make a DLL in C#?
You need to use the /target:library compiler option.
How do I simulate optional parameters to COM calls?
You must use the Missing class and pass Missing.Value (in System.Reflection) for any values that have optional parameters.
Will finally block get executed if the exception had not occurred?
Yes.
What is the C# equivalent of C++ catch (…), which was a catch-all statement for any possible exception? Does C# support try-catch-finally blocks?
Yes. Try-catch-finally blocks are supported by the C# compiler. Here's an example of a try-catch-finally block: using System;
public class TryTest
{
static void Main()
{
try
{
Console.WriteLine("In Try block");
throw new ArgumentException();
}
catch(ArgumentException n1)
{
Console.WriteLine("Catch Block");
}
finally
{
Console.WriteLine("Finally Block");
}
}
}
Output: In Try Block
Catch Block
Finally Block
If I return out of a try/finally in C#, does the code in the finally-clause run? Yes. The code in the finally always runs. If you return out of the try block, or even if you do a "goto" out of the try, the finally block always runs, as shown in the following
example: using System;
class main
{
public static void Main()
{
try
{
Console.WriteLine("In Try block");
return;
}
finally
{
Console.WriteLine("In Finally block");
}
}
}
Both "In Try block" and "In Finally block" will be displayed. Whether the return is in the try block or after the try-finally block, performance is not affected either way. The compiler treats it as if the return were outside the try block anyway. If it's a return without an expression (as it is above), the IL emitted is identical whether the return is inside or outside of the try. If the return has an expression, there's an extra store/load of the value of the expression (since it has to be computed within the try block).
C Interview Questions 2
How do you mark a method obsolete?
[Obsolete] public int Foo() {...}
or
[Obsolete(\"This is a message describing why this method is obsolete\")] public int Foo() {...}
Note: The O in Obsolete is always capitalized.
How do you implement thread synchronization (Object.Wait, Notify,and CriticalSection) in C#?
You want the lock statement, which is the same as Monitor Enter/Exit:
lock(obj) { // code }
translates to
try {
CriticalSection.Enter(obj);
// code
}
finally
{
CriticalSection.Exit(obj);
}
How do you directly call a native function exported from a DLL?
Here’s a quick example of the DllImport attribute in action:
using System.Runtime.InteropServices; \
class C
{
[DllImport(\"user32.dll\")]
public static extern int MessageBoxA(int h, string m, string c, int type);
public static int Main()
{
return MessageBoxA(0, \"Hello World!\", \"Caption\", 0);
}
}
This example shows the minimum requirements for declaring a C# method that is implemented in a native DLL. The method C.MessageBoxA() is declared with the static and external modifiers, and has the DllImport attribute, which tells the compiler that the implementation comes from the user32.dll, using the default name of MessageBoxA. For more information, look at the Platform Invoke tutorial in the documentation.
How do I simulate optional parameters to COM calls?
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You must use the Missing class and pass Missing.Value (in System.Reflection) for any values that have optional parameters.
What do you know about .NET assemblies?
Assemblies are the smallest units of versioning and deployment in the .NET application. Assemblies are also the building blocks for programs such as Web services, Windows services, serviced components, and .NET remoting applications.
What’s the difference between private and shared assembly?
Private assembly is used inside an application only and does not have to be identified by a strong name. Shared assembly can be used by multiple applications and has to have a strong name.
What’s a strong name?
A strong name includes the name of the assembly, version number, culture identity, and a public key token.
How can you tell the application to look for assemblies at the locations other than its own install?
Use the directive in the XML .config file for a given application.
< probing privatePath=c:\mylibs; bin\debug />
should do the trick. Or you can add additional search paths in the Properties box of the deployed application.
How can you debug failed assembly binds?
Use the Assembly Binding Log Viewer (fuslogvw.exe) to find out the paths searched.
Where are shared assemblies stored?
Global assembly cache.
How can you create a strong name for a .NET assembly?
With the help of Strong Name tool (sn.exe).
Where’s global assembly cache located on the system?
Usually C:\winnt\assembly or C:\windows\assembly.
Can you have two files with the same file name in GAC?
Yes, remember that GAC is a very special folder, and while normally you would not be able to place two files with the same name into a Windows folder, GAC differentiates by version number as well, so it’s possible for MyApp.dll and MyApp.dll to co-exist in GAC if the first one is version 1.0.0.0 and the second one is 1.1.0.0.
[Obsolete] public int Foo() {...}
or
[Obsolete(\"This is a message describing why this method is obsolete\")] public int Foo() {...}
Note: The O in Obsolete is always capitalized.
How do you implement thread synchronization (Object.Wait, Notify,and CriticalSection) in C#?
You want the lock statement, which is the same as Monitor Enter/Exit:
lock(obj) { // code }
translates to
try {
CriticalSection.Enter(obj);
// code
}
finally
{
CriticalSection.Exit(obj);
}
How do you directly call a native function exported from a DLL?
Here’s a quick example of the DllImport attribute in action:
using System.Runtime.InteropServices; \
class C
{
[DllImport(\"user32.dll\")]
public static extern int MessageBoxA(int h, string m, string c, int type);
public static int Main()
{
return MessageBoxA(0, \"Hello World!\", \"Caption\", 0);
}
}
This example shows the minimum requirements for declaring a C# method that is implemented in a native DLL. The method C.MessageBoxA() is declared with the static and external modifiers, and has the DllImport attribute, which tells the compiler that the implementation comes from the user32.dll, using the default name of MessageBoxA. For more information, look at the Platform Invoke tutorial in the documentation.
How do I simulate optional parameters to COM calls?
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You must use the Missing class and pass Missing.Value (in System.Reflection) for any values that have optional parameters.
What do you know about .NET assemblies?
Assemblies are the smallest units of versioning and deployment in the .NET application. Assemblies are also the building blocks for programs such as Web services, Windows services, serviced components, and .NET remoting applications.
What’s the difference between private and shared assembly?
Private assembly is used inside an application only and does not have to be identified by a strong name. Shared assembly can be used by multiple applications and has to have a strong name.
What’s a strong name?
A strong name includes the name of the assembly, version number, culture identity, and a public key token.
How can you tell the application to look for assemblies at the locations other than its own install?
Use the directive in the XML .config file for a given application.
< probing privatePath=c:\mylibs; bin\debug />
should do the trick. Or you can add additional search paths in the Properties box of the deployed application.
How can you debug failed assembly binds?
Use the Assembly Binding Log Viewer (fuslogvw.exe) to find out the paths searched.
Where are shared assemblies stored?
Global assembly cache.
How can you create a strong name for a .NET assembly?
With the help of Strong Name tool (sn.exe).
Where’s global assembly cache located on the system?
Usually C:\winnt\assembly or C:\windows\assembly.
Can you have two files with the same file name in GAC?
Yes, remember that GAC is a very special folder, and while normally you would not be able to place two files with the same name into a Windows folder, GAC differentiates by version number as well, so it’s possible for MyApp.dll and MyApp.dll to co-exist in GAC if the first one is version 1.0.0.0 and the second one is 1.1.0.0.
C Interview Questions
What's C# ?
C# (pronounced C-sharp) is a new object oriented language from Microsoft and is derived from C and C++. It also borrows a lot of concepts from Java too including garbage collection.
Is it possible to inline assembly or IL in C# code?
- No.
Is it possible to have different access modifiers on the get/set methods of a property?
- No. The access modifier on a property applies to both its get and set accessors. What you need to do if you want them to be different is make the property read-only (by only providing a get accessor) and create a private/internal set method that is separate from the property.
Is it possible to have a static indexer in C#? allowed in C#.
- No. Static indexers are not
If I return out of a try/finally in C#, does the code in the finally-clause run?
-Yes. The code in the finally always runs. If you return out of the try block, or even if you do a goto out of the try, the finally block always runs:
using System;
class main
{
public static void Main()
{
try
{
Console.WriteLine(\"In Try block\");
return;
}
finally
{
Console.WriteLine(\"In Finally block\");
}
}
}
Both In Try block and In Finally block will be displayed. Whether the return is in the try block or after the try-finally block, performance is not affected either way. The compiler treats it as if the return were outside the try block anyway. If it’s a return without an expression (as it is above), the IL emitted is identical whether the return is inside or outside of the try. If the return has an expression, there’s an extra store/load of the value of the expression (since it has to be computed within the try block).
I was trying to use an out int parameter in one of my functions. How should I declare the variable that I am passing to it?
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You should declare the variable as an int, but when you pass it in you must specify it as ‘out’, like the following: int i; foo(out i); where foo is declared as follows:
[return-type] foo(out int o) { }
How does one compare strings in C#?
In the past, you had to call .ToString() on the strings when using the == or != operators to compare the strings’ values. That will still work, but the C# compiler now automatically compares the values instead of the references when the == or != operators are used on string types. If you actually do want to compare references, it can be done as follows: if ((object) str1 == (object) str2) { } Here’s an example showing how string compares work:
using System;
public class StringTest
{
public static void Main(string[] args)
{
Object nullObj = null; Object realObj = new StringTest();
int i = 10;
Console.WriteLine(\"Null Object is [\" + nullObj + \"]\n\"
+ \"Real Object is [\" + realObj + \"]\n\"
+ \"i is [\" + i + \"]\n\");
// Show string equality operators
string str1 = \"foo\";
string str2 = \"bar\";
string str3 = \"bar\";
Console.WriteLine(\"{0} == {1} ? {2}\", str1, str2, str1 == str2 );
Console.WriteLine(\"{0} == {1} ? {2}\", str2, str3, str2 == str3 );
}
}
Output:
Null Object is []
Real Object is [StringTest]
i is [10]
foo == bar ? False
bar == bar ? True
How do you specify a custom attribute for the entire assembly (rather than for a class)?
Global attributes must appear after any top-level using clauses and before the first type or namespace declarations. An example of this is as follows:
using System;
[assembly : MyAttributeClass] class X {}
Note that in an IDE-created project, by convention, these attributes are placed in AssemblyInfo.cs.
C# (pronounced C-sharp) is a new object oriented language from Microsoft and is derived from C and C++. It also borrows a lot of concepts from Java too including garbage collection.
Is it possible to inline assembly or IL in C# code?
- No.
Is it possible to have different access modifiers on the get/set methods of a property?
- No. The access modifier on a property applies to both its get and set accessors. What you need to do if you want them to be different is make the property read-only (by only providing a get accessor) and create a private/internal set method that is separate from the property.
Is it possible to have a static indexer in C#? allowed in C#.
- No. Static indexers are not
If I return out of a try/finally in C#, does the code in the finally-clause run?
-Yes. The code in the finally always runs. If you return out of the try block, or even if you do a goto out of the try, the finally block always runs:
using System;
class main
{
public static void Main()
{
try
{
Console.WriteLine(\"In Try block\");
return;
}
finally
{
Console.WriteLine(\"In Finally block\");
}
}
}
Both In Try block and In Finally block will be displayed. Whether the return is in the try block or after the try-finally block, performance is not affected either way. The compiler treats it as if the return were outside the try block anyway. If it’s a return without an expression (as it is above), the IL emitted is identical whether the return is inside or outside of the try. If the return has an expression, there’s an extra store/load of the value of the expression (since it has to be computed within the try block).
I was trying to use an out int parameter in one of my functions. How should I declare the variable that I am passing to it?
Security Tip
Use Firefox instead of Internet Explorer and PREVENT Spyware !
Firefox is free and is considered the best free, safe web browser available today
Browse the web faster. Get Firefox with Google Toolbar
You should declare the variable as an int, but when you pass it in you must specify it as ‘out’, like the following: int i; foo(out i); where foo is declared as follows:
[return-type] foo(out int o) { }
How does one compare strings in C#?
In the past, you had to call .ToString() on the strings when using the == or != operators to compare the strings’ values. That will still work, but the C# compiler now automatically compares the values instead of the references when the == or != operators are used on string types. If you actually do want to compare references, it can be done as follows: if ((object) str1 == (object) str2) { } Here’s an example showing how string compares work:
using System;
public class StringTest
{
public static void Main(string[] args)
{
Object nullObj = null; Object realObj = new StringTest();
int i = 10;
Console.WriteLine(\"Null Object is [\" + nullObj + \"]\n\"
+ \"Real Object is [\" + realObj + \"]\n\"
+ \"i is [\" + i + \"]\n\");
// Show string equality operators
string str1 = \"foo\";
string str2 = \"bar\";
string str3 = \"bar\";
Console.WriteLine(\"{0} == {1} ? {2}\", str1, str2, str1 == str2 );
Console.WriteLine(\"{0} == {1} ? {2}\", str2, str3, str2 == str3 );
}
}
Output:
Null Object is []
Real Object is [StringTest]
i is [10]
foo == bar ? False
bar == bar ? True
How do you specify a custom attribute for the entire assembly (rather than for a class)?
Global attributes must appear after any top-level using clauses and before the first type or namespace declarations. An example of this is as follows:
using System;
[assembly : MyAttributeClass] class X {}
Note that in an IDE-created project, by convention, these attributes are placed in AssemblyInfo.cs.
.Net Web Interview Questions and Answers 5
What is used to validate complex string patterns like an e-mail address?
* Extended expressions
* Regular expressions
* Irregular expressions
* Basic expressions
Regular Expression.
The following is a valid statement in ASP.NET<%@ Page Language="C" %>
* True
* False
False
A valid comment block in ASP.NET is
*
*
* <% - - Comment - - %>
* <% ! - - Comment - - >
<% - - Comment - - %>
The event handlers that can be included in the Global.asax file are
* Application Start and
Session Start event handlers only
* Application End and
Session End event handlers only
* Per-request and Non-deterministic event handlers only
* Application Start and End ,
Application Start and End
A Few of the Namespaces that get imported by default in an ASPX file are
* System, System.Data, System.Drawing,
System.Globalization
* System,
System.IO, System.Management, System.Globalization
* System, System.Collections,
System.Text, System.Web
* System,
System.NET,
System.Reflection, System.Web
System, System.Collections, System.Text, System.Web
The Assemblies that can be referenced in an ASPX file without using @Assembly Directive is
* System.dll, System.Data.dll,
System.Web.dll, System.Xml.dll,
* System.dll,
System.Collections.dll, System.IO.dll
* System.dll, System.Reflection.dll,
System.Globalization.dll,
* System.Drawing.dll, System.Assembly.dll,
System.Text.dll
System.dll, System.Data.dll, System.Web.dll, System.Xml.dll
An .ASHX file contains the following
* Code-behind that are used in the code
* Server Controls that can be called from a code-behind file
* HTTP handlers-software modules that handle raw HTTP requests received by ASP.NET
* Contains normal ASP.NET code and can be used as an include file
HTTP handlers-software modules that handle raw HTTP requests received by ASP.NET
What is the output for the following code snippet:
public class testClass
{
public static void Main(string[] args)
{
System.Console.WriteLine(args[1]);
}//end Main
}//end class testClass
* Compiler Error
* Runtime Error
* Hello C# world
* None of the above
Runtime Error
One of the possible way of writing an ASP.NET handler that works like an ISAPI filter- that is, that sees requests and responses and modifies them also, is by,
* writing a module that extends FormsAuthenticatonModule and using it
* writing a component class that extends HttpModuleCollection and using it
* writing an HTTP module-a Class that implements IhttpModule and registering it in Web.Config
* All of the above
writing an HTTP module-a Class that implements IhttpModule and registering it in Web.Config
The ASP.NET directive that lets you cache different versions of a page based on varying input parameters, HTTP headers and browser type is
* @OutputCache
* @CacheOutput
* @PageCache
* @CacheAll
@ OutputCache
If we develop an application that must accommodate multiple security levels through secure login and ASP.NET web application is spanned across three web-servers (using round-robin load balancing) what would be the best approach to maintain login-in state for the users?
*
*
*
SessionState mode=”stateserver” stateConnectionString=”tcpip=127.0.0.1:42424? sqlConnectionString=”data source=127.0.0.1;user id=sa;password=” cookieless=”false” timeout=”30?
What is the output for the below mentioned compilation command>csc /addmodule:A.Exe B.Cs
* A.exe
* B.exe
* A.dll
* B.dll
B.exe
How can be the web application get configured with the following authorization rules
* Anonymous users must not be allowed to access the application.
* All persons except David and John must be allowed to access the application.
o<
o
o
o
authorization deny users = “applicationname\David, applicationname\John” deny users = “?” allow users =”*” /authorization
What will be the output of the following code snippet?
using System;
class MainClass
{
static void Main( )
{
new MainClass().Display( 3.56 );
}
private void Display( float anArg )
{
Console.Write( “{0} {1}”, anArg.GetType(), anArg );
}
double Display( double anArg )
{
Console.Write( “{0} {1}”, anArg.GetType(), anArg );
return anArg;
}
public decimal Display( decimal anArg )
{
Console.Write( “{0} {1}”, anArg.GetType(), anArg ); return anArg;
}
}
* System.Single 3.56
* System.Float 3.56
* System.Double 3.56
* System.Decimal 3.56
System.Double 3.56
What will be output for the given code?
Dim I as integer = 5
Do
I = I + 2
Response.Write (I & " ")
Loop Until I > 10
* 5 8
* 5 7 9
* 7 9 11
* Errors out
7 9 11 (if corrected)
* Extended expressions
* Regular expressions
* Irregular expressions
* Basic expressions
Regular Expression.
The following is a valid statement in ASP.NET<%@ Page Language="C" %>
* True
* False
False
A valid comment block in ASP.NET is
*
*
* <% - - Comment - - %>
* <% ! - - Comment - - >
<% - - Comment - - %>
The event handlers that can be included in the Global.asax file are
* Application Start and
Session Start event handlers only
* Application End and
Session End event handlers only
* Per-request and Non-deterministic event handlers only
* Application Start and End ,
Application Start and End
A Few of the Namespaces that get imported by default in an ASPX file are
* System, System.Data, System.Drawing,
System.Globalization
* System,
System.IO, System.Management, System.Globalization
* System, System.Collections,
System.Text, System.Web
* System,
System.NET,
System.Reflection, System.Web
System, System.Collections, System.Text, System.Web
The Assemblies that can be referenced in an ASPX file without using @Assembly Directive is
* System.dll, System.Data.dll,
System.Web.dll, System.Xml.dll,
* System.dll,
System.Collections.dll, System.IO.dll
* System.dll, System.Reflection.dll,
System.Globalization.dll,
* System.Drawing.dll, System.Assembly.dll,
System.Text.dll
System.dll, System.Data.dll, System.Web.dll, System.Xml.dll
An .ASHX file contains the following
* Code-behind that are used in the code
* Server Controls that can be called from a code-behind file
* HTTP handlers-software modules that handle raw HTTP requests received by ASP.NET
* Contains normal ASP.NET code and can be used as an include file
HTTP handlers-software modules that handle raw HTTP requests received by ASP.NET
What is the output for the following code snippet:
public class testClass
{
public static void Main(string[] args)
{
System.Console.WriteLine(args[1]);
}//end Main
}//end class testClass
* Compiler Error
* Runtime Error
* Hello C# world
* None of the above
Runtime Error
One of the possible way of writing an ASP.NET handler that works like an ISAPI filter- that is, that sees requests and responses and modifies them also, is by,
* writing a module that extends FormsAuthenticatonModule and using it
* writing a component class that extends HttpModuleCollection and using it
* writing an HTTP module-a Class that implements IhttpModule and registering it in Web.Config
* All of the above
writing an HTTP module-a Class that implements IhttpModule and registering it in Web.Config
The ASP.NET directive that lets you cache different versions of a page based on varying input parameters, HTTP headers and browser type is
* @OutputCache
* @CacheOutput
* @PageCache
* @CacheAll
@ OutputCache
If we develop an application that must accommodate multiple security levels through secure login and ASP.NET web application is spanned across three web-servers (using round-robin load balancing) what would be the best approach to maintain login-in state for the users?
*
*
*
SessionState mode=”stateserver” stateConnectionString=”tcpip=127.0.0.1:42424? sqlConnectionString=”data source=127.0.0.1;user id=sa;password=” cookieless=”false” timeout=”30?
What is the output for the below mentioned compilation command>csc /addmodule:A.Exe B.Cs
* A.exe
* B.exe
* A.dll
* B.dll
B.exe
How can be the web application get configured with the following authorization rules
* Anonymous users must not be allowed to access the application.
* All persons except David and John must be allowed to access the application.
o
o
o
o
authorization deny users = “applicationname\David, applicationname\John” deny users = “?” allow users =”*” /authorization
What will be the output of the following code snippet?
using System;
class MainClass
{
static void Main( )
{
new MainClass().Display( 3.56 );
}
private void Display( float anArg )
{
Console.Write( “{0} {1}”, anArg.GetType(), anArg );
}
double Display( double anArg )
{
Console.Write( “{0} {1}”, anArg.GetType(), anArg );
return anArg;
}
public decimal Display( decimal anArg )
{
Console.Write( “{0} {1}”, anArg.GetType(), anArg ); return anArg;
}
}
* System.Single 3.56
* System.Float 3.56
* System.Double 3.56
* System.Decimal 3.56
System.Double 3.56
What will be output for the given code?
Dim I as integer = 5
Do
I = I + 2
Response.Write (I & " ")
Loop Until I > 10
* 5 8
* 5 7 9
* 7 9 11
* Errors out
7 9 11 (if corrected)
.Net Web Interview Questions and Answers 4
Which one of the following objects is used to create a foreign key between two DataTables?
* DataRelation
* DataRelationship
* DataConstraint
* DataKey
DataRelation
The Syntax for data-binding expressions is
* <%# property or collection %>
* <%# property or collection #%>
* <%$ property or collection %>
* <%@ property or collection %>
<%# property or collection #%>
The method that need to be invoked on the DataAdapter control to load the generated dataset with data is
* Bind()
* Fill()
* FillData()
* SetData()
Fill()
Which of the following operations can you NOT perform on an ADO.NET DataSet?
* A DataSet can be synchronised with the database.
* A DataSet can be synchronised with a RecordSet.
* A DataSet can be converted to XML.
* You can infer the schema from a DataSet
A DataSet can be synchronised with a RecordSet.
Which is the correct statement to set the alias name for namespace in C#?
* using System Data.OracleClient = aliasName;
* using aliasName = System.Data.OracleClient;
* string aliasName = using.System.Data.OracleClient;
* Both a & b
using aliasName = System.Data.OracleClient;
The property that indicates whether existing database constraints should be observed when performing updates
* EnforceConstraints
* Constraints
* GetConstraints
* ConstraintsEnforce
EnforceConstraints
State True or False: If you set AutoGenerateColumns=True and still provide custom column definitions, the DataGrid will render both
* True
* False
False.
The data from an XSL Transform with XmlReader can be returned in one of the following ways
* objReader = objXslT.Transform(objNav, nothing)
* objXslT.Transform(objNav, nothing)
* objReader = objXslT.Transform(objNav, nothing, objWriter)
* objXslT.Transform(objNav, nothing, objWriter)
objXslT.Transform(objNav, nothing)
Pick the command line that would result in the C# compiler generating an XML documentation file
* csc /doc:NewHome.xml NewHome.cs
* c /doc /docfile: NewHome.xml NewHome.cs
* csc /doc /out: NewHome.xml NewHome.cs
* csc /xml NewHome.cs
csc /doc:NewHome.xml NewHome.cs
What is the comment syntax for C#’s XML-based documentation? * /** and **/ * //# * /// * //*
///
When creating a C# Class Library project, what is the name of the supplementary file that Visual Studio.NET creates that contains General Information about the assembly?
* AssemblyInfo.xml
* AssemblyInfo.cs
* AssemblyInformation.cs
* AssemblyAttributes.cs
AssemblyInfo.cs
Which of the following is the C# escape character for Null?
* \n
* \0
* \f
* \v
\0
What is the exception that is thrown when there is an attempt to dynamically access a method that does not exist?
* MissingMethodException
* TypeLoadException
* MethodLoadException
* MethodAccessException
MissingMethodException
What method(s) must be used with the Application object to ensure that only one process accesses a variable at a time?
* Synchronize()
* Lock() and UnLock()
* Lock()
* Asynchroize()
Lock()
After capturing the SelectedIndexChanged event for a ListBox control, you find that the event handler doesn’t execute. What could the problem be?
* The AutoEventWireup attribute is set to False
* The AutomaticPostBack attribute is set to False
* The codebehind module is not properly compiled
* The ListBox must be defined WithEvents
AutoPostBack attribute is set to False
What method must be overridden in a custom control?
* The Paint() method
* The Control_Build() method
* The Render() method
* The default constructor
The Render() method
* DataRelation
* DataRelationship
* DataConstraint
* DataKey
DataRelation
The Syntax for data-binding expressions is
* <%# property or collection %>
* <%# property or collection #%>
* <%$ property or collection %>
* <%@ property or collection %>
<%# property or collection #%>
The method that need to be invoked on the DataAdapter control to load the generated dataset with data is
* Bind()
* Fill()
* FillData()
* SetData()
Fill()
Which of the following operations can you NOT perform on an ADO.NET DataSet?
* A DataSet can be synchronised with the database.
* A DataSet can be synchronised with a RecordSet.
* A DataSet can be converted to XML.
* You can infer the schema from a DataSet
A DataSet can be synchronised with a RecordSet.
Which is the correct statement to set the alias name for namespace in C#?
* using System Data.OracleClient = aliasName;
* using aliasName = System.Data.OracleClient;
* string aliasName = using.System.Data.OracleClient;
* Both a & b
using aliasName = System.Data.OracleClient;
The property that indicates whether existing database constraints should be observed when performing updates
* EnforceConstraints
* Constraints
* GetConstraints
* ConstraintsEnforce
EnforceConstraints
State True or False: If you set AutoGenerateColumns=True and still provide custom column definitions, the DataGrid will render both
* True
* False
False.
The data from an XSL Transform with XmlReader can be returned in one of the following ways
* objReader = objXslT.Transform(objNav, nothing)
* objXslT.Transform(objNav, nothing)
* objReader = objXslT.Transform(objNav, nothing, objWriter)
* objXslT.Transform(objNav, nothing, objWriter)
objXslT.Transform(objNav, nothing)
Pick the command line that would result in the C# compiler generating an XML documentation file
* csc /doc:NewHome.xml NewHome.cs
* c /doc /docfile: NewHome.xml NewHome.cs
* csc /doc /out: NewHome.xml NewHome.cs
* csc /xml NewHome.cs
csc /doc:NewHome.xml NewHome.cs
What is the comment syntax for C#’s XML-based documentation? * /** and **/ * //# * /// * //*
///
When creating a C# Class Library project, what is the name of the supplementary file that Visual Studio.NET creates that contains General Information about the assembly?
* AssemblyInfo.xml
* AssemblyInfo.cs
* AssemblyInformation.cs
* AssemblyAttributes.cs
AssemblyInfo.cs
Which of the following is the C# escape character for Null?
* \n
* \0
* \f
* \v
\0
What is the exception that is thrown when there is an attempt to dynamically access a method that does not exist?
* MissingMethodException
* TypeLoadException
* MethodLoadException
* MethodAccessException
MissingMethodException
What method(s) must be used with the Application object to ensure that only one process accesses a variable at a time?
* Synchronize()
* Lock() and UnLock()
* Lock()
* Asynchroize()
Lock()
After capturing the SelectedIndexChanged event for a ListBox control, you find that the event handler doesn’t execute. What could the problem be?
* The AutoEventWireup attribute is set to False
* The AutomaticPostBack attribute is set to False
* The codebehind module is not properly compiled
* The ListBox must be defined WithEvents
AutoPostBack attribute is set to False
What method must be overridden in a custom control?
* The Paint() method
* The Control_Build() method
* The Render() method
* The default constructor
The Render() method
.Net Web Interview Questions and Answers 3
The Equivalent HTML Control for the tag is
* HtmlInput
* HtmlButton
* HtmlPushButton
* HtmlInputButton
HtmlInputButton
The Equivalent Html Control for the tag is
* HtmlCheckBox
* HtmlInputChkBox
* HtmlInputCheckBox
* HtmlInputTypeChkBox
HtmlInputCheckBox
Which operator is used for connecting a event with a procedure in C#?
* +=
* =
* both
* none
+=
The Equivalent Html Control for the
* HtmlInput
* HtmlButton
* HtmlPushButton
* HtmlInputButton
HtmlInputButton
The Equivalent Html Control for the tag is
* HtmlCheckBox
* HtmlInputChkBox
* HtmlInputCheckBox
* HtmlInputTypeChkBox
HtmlInputCheckBox
Which operator is used for connecting a event with a procedure in C#?
* +=
* =
* both
* none
+=
The Equivalent Html Control for the
Which of the following operators has the highest precedence?
* Pre Increment (++x)
* Shift bits left: <<
* Bitwise Or: |
* Post Increment (x++)
Shift bits left
The uniqueId that gets generated at the start of the Session is stored in
* Client computer as a cookie
* Server machine
* Passed to and fro on each and every request and response
* Both a and b are correct
Both a and b are correct
State True or False: C# supports multiple-inheritance
* True
* False
False
Bitwise AND operator in C# is
* &
* &&
* AND
* XAND
Answer1:
&&
Answer2:
&
Bitwise OR operator in C# is
* OR
* ||
* |
* XOR
Answer1:
||
Answer2:
|
What’s the .NET datatype that allows the retrieval of data by a unique key?
* Primary
* Integer
* Unique Identifier
* HashTable
* Pre Increment (++x)
* Shift bits left: <<
* Bitwise Or: |
* Post Increment (x++)
Shift bits left
The uniqueId that gets generated at the start of the Session is stored in
* Client computer as a cookie
* Server machine
* Passed to and fro on each and every request and response
* Both a and b are correct
Both a and b are correct
State True or False: C# supports multiple-inheritance
* True
* False
False
Bitwise AND operator in C# is
* &
* &&
* AND
* XAND
Answer1:
&&
Answer2:
&
Bitwise OR operator in C# is
* OR
* ||
* |
* XOR
Answer1:
||
Answer2:
|
What’s the .NET datatype that allows the retrieval of data by a unique key?
* Primary
* Integer
* Unique Identifier
* HashTable
.Net Web Interview Questions and Answers
Which of the following languages is NOT included in the default .NET Framework installation?
* C#
* VB.NET
* JScript.NET
* VBScript.NET
VBScript.NET
What are the different types of serialization supported in .NET Framework
* XmlSerializer
* SoapFormatter
* XPathNavigator
* HttpFormatter
xmlserializer
The CLR uses which format for assembly version numbers
* Major:Minor:Revision:Build
* Major:Build:Minor:Revision
* Major:Revision:Minor:Build
* Major:Minor:Build:Revision
Major:Minor:Build:Revision
What tool is used to manage the GAC?
* GacMgr.exe
* GacSvr32.exe
* GacUtil.exe
* RegSvr.exe
GacUtil.exe
State True or False: A single .NET dll can contain unlimited classes
* True
* False
True
State True or False: ASP.NET can currently run only on Windows Platform
* True
* False
True
Which one of the following best describes “Type-Safe”
* It ensures that the data type are safely handled
* It ensures that types are not mismatched when they are called so uses a typecasting before referencing any data object
* It ensures that an object only references memory locations that it’s allowed to, preventing data corruption and the accidental misuse of object types
* All of the above
All of the above
The number of objects in ASP.NET is
* 6
* 7
* 9
* 10
Answer1:
7
Answer2:
10
The code used to turn off buffering is
* Buffering = false
* OutputBuffer = false
* BufferOutput = false
* Buffer = Off
Answer1:
Buffer=true
Answer2:
Buffer=false
Can you have two applications on the same machine one which is using .NET Framework 1.1 and the other using 2.0 ?
* Yes
* No
* Depends on System configuration
Yes
Which of the following DOT.NET tools manages certificates, certificate trust lists (CTLs), and certificate revocation lists (CRLs)?
* sn.exe
* certnet.exe
* certmgr.exe
* gacutil.exe
certmgr.exe
You need to generate a public/private key pair for using in creating a shared assembly. Given the above scenario, which .NET SDK utility should be used?
* certmgr.exe
* gacutil.exe
* sn.exe
* resgen.exe
sn.exe
The object that contains all the properties and methods for every ASP.NET page, that is built is
* Page Object
* HTTPPage Object
* WebPage Object
* System.Web.UI.Page
Page Object
In C#, which character is used to indicate a verbatim string literal?
* @
* !
* "
* #
@
* C#
* VB.NET
* JScript.NET
* VBScript.NET
VBScript.NET
What are the different types of serialization supported in .NET Framework
* XmlSerializer
* SoapFormatter
* XPathNavigator
* HttpFormatter
xmlserializer
The CLR uses which format for assembly version numbers
* Major:Minor:Revision:Build
* Major:Build:Minor:Revision
* Major:Revision:Minor:Build
* Major:Minor:Build:Revision
Major:Minor:Build:Revision
What tool is used to manage the GAC?
* GacMgr.exe
* GacSvr32.exe
* GacUtil.exe
* RegSvr.exe
GacUtil.exe
State True or False: A single .NET dll can contain unlimited classes
* True
* False
True
State True or False: ASP.NET can currently run only on Windows Platform
* True
* False
True
Which one of the following best describes “Type-Safe”
* It ensures that the data type are safely handled
* It ensures that types are not mismatched when they are called so uses a typecasting before referencing any data object
* It ensures that an object only references memory locations that it’s allowed to, preventing data corruption and the accidental misuse of object types
* All of the above
All of the above
The number of objects in ASP.NET is
* 6
* 7
* 9
* 10
Answer1:
7
Answer2:
10
The code used to turn off buffering is
* Buffering = false
* OutputBuffer = false
* BufferOutput = false
* Buffer = Off
Answer1:
Buffer=true
Answer2:
Buffer=false
Can you have two applications on the same machine one which is using .NET Framework 1.1 and the other using 2.0 ?
* Yes
* No
* Depends on System configuration
Yes
Which of the following DOT.NET tools manages certificates, certificate trust lists (CTLs), and certificate revocation lists (CRLs)?
* sn.exe
* certnet.exe
* certmgr.exe
* gacutil.exe
certmgr.exe
You need to generate a public/private key pair for using in creating a shared assembly. Given the above scenario, which .NET SDK utility should be used?
* certmgr.exe
* gacutil.exe
* sn.exe
* resgen.exe
sn.exe
The object that contains all the properties and methods for every ASP.NET page, that is built is
* Page Object
* HTTPPage Object
* WebPage Object
* System.Web.UI.Page
Page Object
In C#, which character is used to indicate a verbatim string literal?
* @
* !
* "
* #
@
dotnet
What do you know about .NET assemblies?
Assemblies are the smallest units of versioning and deployment in the .NET application. Assemblies are also the building blocks for programs such as Web services, Windows services, serviced components, and .NET Remoting applications.
What’s the difference between private and shared assembly?
Private assembly is used inside an application only and does not have to be identified by a strong name. Shared assembly can be used by multiple applications and has to have a strong name.
What’s a strong name?
A strong name includes the name of the assembly, version number, culture identity, and a public key token.
How can you tell the application to look for assemblies at the locations other than its own install?
Use the
directive in the XML .config file for a given application.
should do the trick. Or you can add additional search paths in the Properties box of the deployed application.
How can you debug failed assembly binds?
Use the Assembly Binding Log Viewer (fuslogvw.exe) to find out the paths searched.
Where are shared assemblies stored?
Global assembly cache.
How can you create a strong name for a .NET assembly?
With the help of Strong Name tool (sn.exe).
Where’s global assembly cache located on the system?
Usually C:\winnt\assembly or C:\windows\assembly.
Can you have two files with the same file name in GAC?
Yes, remember that GAC is a very special folder, and while normally you would not be able to place two files with the same name into a Windows folder, GAC differentiates by version number as well, so it’s possible for MyApp.dll and MyApp.dll to co-exist in GAC if the first one is version 1.0.0.0 and the second one is 1.1.0.0.
So let’s say I have an application that uses MyApp.dll assembly, version 1.0.0.0. There is a security bug in that assembly, and I publish the patch, issuing it under name MyApp.dll 1.1.0.0. How do I tell the client applications that are already installed to start using this new MyApp.dll?
Use publisher policy. To configure a publisher policy, use the publisher policy configuration file, which uses a format similar app .config file. But unlike the app .config file, a publisher policy file needs to be compiled into an assembly and placed in the GAC.
What is delay signing?
Delay signing allows you to place a shared assembly in the GAC by signing the assembly with just the public key. This allows the assembly to be signed with the private key at a later stage, when the development process is complete and the component or assembly is ready to be deployed. This process enables developers to work with shared assemblies as if they were strongly named, and it secures the private key of the signature from being accessed at different stages of development.
Assemblies are the smallest units of versioning and deployment in the .NET application. Assemblies are also the building blocks for programs such as Web services, Windows services, serviced components, and .NET Remoting applications.
What’s the difference between private and shared assembly?
Private assembly is used inside an application only and does not have to be identified by a strong name. Shared assembly can be used by multiple applications and has to have a strong name.
What’s a strong name?
A strong name includes the name of the assembly, version number, culture identity, and a public key token.
How can you tell the application to look for assemblies at the locations other than its own install?
Use the
directive in the XML .config file for a given application.
should do the trick. Or you can add additional search paths in the Properties box of the deployed application.
How can you debug failed assembly binds?
Use the Assembly Binding Log Viewer (fuslogvw.exe) to find out the paths searched.
Where are shared assemblies stored?
Global assembly cache.
How can you create a strong name for a .NET assembly?
With the help of Strong Name tool (sn.exe).
Where’s global assembly cache located on the system?
Usually C:\winnt\assembly or C:\windows\assembly.
Can you have two files with the same file name in GAC?
Yes, remember that GAC is a very special folder, and while normally you would not be able to place two files with the same name into a Windows folder, GAC differentiates by version number as well, so it’s possible for MyApp.dll and MyApp.dll to co-exist in GAC if the first one is version 1.0.0.0 and the second one is 1.1.0.0.
So let’s say I have an application that uses MyApp.dll assembly, version 1.0.0.0. There is a security bug in that assembly, and I publish the patch, issuing it under name MyApp.dll 1.1.0.0. How do I tell the client applications that are already installed to start using this new MyApp.dll?
Use publisher policy. To configure a publisher policy, use the publisher policy configuration file, which uses a format similar app .config file. But unlike the app .config file, a publisher policy file needs to be compiled into an assembly and placed in the GAC.
What is delay signing?
Delay signing allows you to place a shared assembly in the GAC by signing the assembly with just the public key. This allows the assembly to be signed with the private key at a later stage, when the development process is complete and the component or assembly is ready to be deployed. This process enables developers to work with shared assemblies as if they were strongly named, and it secures the private key of the signature from being accessed at different stages of development.
.Net Database Interview Questions 12
Using query analyzer, name 3 ways you can get an accurate count of the number of records in a table.
Answer1.
a. Select count(*) from table1
b. SELECT object_name(id) ,rowcnt FROM sysindexes WHERE indid IN (1,0) AND OBJECTPROPERTY(id, ‘IsUserTable’) = 1
c. exec sp_table_validation @table = ‘authors’
Answer2.
SELECT count( * ) as totalrecords FROM employee
This will display total records under the name totalrecords in the table employee
use COUNT_BIG
Returns the number of items in a group.
@@ROWCOUNT
Returns the number of rows affected by the last statement.
Use this statement after an SQL select * statement, to retrieve the total number of rows in the table
What is the purpose of using COLLATE in a query?
Answer1.
Collation refers to a set of rules that determine how data is sorted and compared. Character data is sorted using rules that define the correct character sequence, with options for specifying case-sensitivity, accent marks, kana character types and character width.
Answer2.
COLLATE is a clause that can be applied to a database definition or a column definition to define the collation, or to a character string expression to apply a collation cast.
What is one of the first things you would do to increase performance of a query? For example, a boss tells you that “a query that ran yesterday took 30 seconds, but today it takes 6 minutes”?
Answer1.
Use Storedprocedure for any optimized result, because it is an compiled code.
Answer2.
One of the best ways to increase query performance is to use indexes.
What is an execution plan? When would you use it? How would you view the execution plan?
The Query Analyzer has a feature called Show Execution Plan. This option allows you to view the execution plan used by SQL Server’s Query Optimizer to actually execute the query. This option is available from the Query menu on the main menu of Query Analyzer, and must be turned on before the query is executed. Once the query is executed, the results of the execution plan are displayed in graphical format in a separate window, available from a tab that appears below the query results window on the screen.
What is the STUFF function and how does it differ from the REPLACE function? Answer1:
stuff-> inserts into it without removing any thing. Replace->replace the given text with the new one.
Answer2:
STUFF - it deletes a specified length of characters and inserts another set of characters at a specified starting point. REPLACE -Replaces all occurrences of a specified string value with another string value.
What does it mean to have quoted_identifier on? What are the implications of having it off?
SET QUOTED_IDENTIFIER ON- Causes SQL Server to follow the SQL-92 rules regarding quotation mark delimiting identifiers and literal strings. Identifiers delimited by double quotation marks can be either Transact-SQL reserved keywords or can contain characters not usually allowed by the Transact-SQL syntax rules for identifiers.
What is the difference between a Local temporary table and a Global temporary table? How is each one used?
Answer1:
Local templrary table will have a single # (#tablename) appended with the table name.Global templrary table will have Double # (##tablename) appended with the table name.
Ex:create table #table1
local temp. table will be available until the session who created it logs out, but global temp. table is available till the last session gets close in SQLServer.
Answer1:
Local temporary tables are visible only in the current session; global temporary tables are visible to all sessions.Prefix local temporary table names with single number sign (#table_name), and prefix global temporary table names with a double number sign (##table_name).
What are cursors? Name four type of cursors and when each one would be applied?
Opening a cursor on a result set allows processing the result set one row at a time.
The four API server cursor types supported by SQL Server are:
a) Static cursors
b) Dynamic cursors
c) Forward-only cursors
d) Keyset-driven cursors
What is the purpose of UPDATE STATISTICS?
UPDATE STATISTICS- it updates information about the distribution of key values for one or more statistics groups (collections) in the specified table or indexed view.
How do you use DBCC statements to monitor various ASPects of a SQL Server installation?
Database Consistency Checker (DBCC) - Is a statement used to check the logical and physical consistency of a database, check memory usage, decrease the size of a database, check performance statistics, and so on. Database consistency checker (DBCC) ensures the physical and logical consistency of a database, but is not corrective. DBCC can help in repairing or checking the installation in case of any failure.
What is referential integrity and how can we achieve it?
Referential integrity preserves the defined relationships between tables when records are entered or deleted. In SQL Server, referential integrity is based on relationships between foreign keys and primary keys or between foreign keys and unique keys. Referential integrity ensures that key values are consistent across tables. Such consistency requires that there be no references to nonexistent values and that if a key value changes, all references to it change consistently throughout the database.
We can achieve this by using foreign key.
Answer1.
a. Select count(*) from table1
b. SELECT object_name(id) ,rowcnt FROM sysindexes WHERE indid IN (1,0) AND OBJECTPROPERTY(id, ‘IsUserTable’) = 1
c. exec sp_table_validation @table = ‘authors’
Answer2.
SELECT count( * ) as totalrecords FROM employee
This will display total records under the name totalrecords in the table employee
use COUNT_BIG
Returns the number of items in a group.
@@ROWCOUNT
Returns the number of rows affected by the last statement.
Use this statement after an SQL select * statement, to retrieve the total number of rows in the table
What is the purpose of using COLLATE in a query?
Answer1.
Collation refers to a set of rules that determine how data is sorted and compared. Character data is sorted using rules that define the correct character sequence, with options for specifying case-sensitivity, accent marks, kana character types and character width.
Answer2.
COLLATE is a clause that can be applied to a database definition or a column definition to define the collation, or to a character string expression to apply a collation cast.
What is one of the first things you would do to increase performance of a query? For example, a boss tells you that “a query that ran yesterday took 30 seconds, but today it takes 6 minutes”?
Answer1.
Use Storedprocedure for any optimized result, because it is an compiled code.
Answer2.
One of the best ways to increase query performance is to use indexes.
What is an execution plan? When would you use it? How would you view the execution plan?
The Query Analyzer has a feature called Show Execution Plan. This option allows you to view the execution plan used by SQL Server’s Query Optimizer to actually execute the query. This option is available from the Query menu on the main menu of Query Analyzer, and must be turned on before the query is executed. Once the query is executed, the results of the execution plan are displayed in graphical format in a separate window, available from a tab that appears below the query results window on the screen.
What is the STUFF function and how does it differ from the REPLACE function? Answer1:
stuff-> inserts into it without removing any thing. Replace->replace the given text with the new one.
Answer2:
STUFF - it deletes a specified length of characters and inserts another set of characters at a specified starting point. REPLACE -Replaces all occurrences of a specified string value with another string value.
What does it mean to have quoted_identifier on? What are the implications of having it off?
SET QUOTED_IDENTIFIER ON- Causes SQL Server to follow the SQL-92 rules regarding quotation mark delimiting identifiers and literal strings. Identifiers delimited by double quotation marks can be either Transact-SQL reserved keywords or can contain characters not usually allowed by the Transact-SQL syntax rules for identifiers.
What is the difference between a Local temporary table and a Global temporary table? How is each one used?
Answer1:
Local templrary table will have a single # (#tablename) appended with the table name.Global templrary table will have Double # (##tablename) appended with the table name.
Ex:create table #table1
local temp. table will be available until the session who created it logs out, but global temp. table is available till the last session gets close in SQLServer.
Answer1:
Local temporary tables are visible only in the current session; global temporary tables are visible to all sessions.Prefix local temporary table names with single number sign (#table_name), and prefix global temporary table names with a double number sign (##table_name).
What are cursors? Name four type of cursors and when each one would be applied?
Opening a cursor on a result set allows processing the result set one row at a time.
The four API server cursor types supported by SQL Server are:
a) Static cursors
b) Dynamic cursors
c) Forward-only cursors
d) Keyset-driven cursors
What is the purpose of UPDATE STATISTICS?
UPDATE STATISTICS- it updates information about the distribution of key values for one or more statistics groups (collections) in the specified table or indexed view.
How do you use DBCC statements to monitor various ASPects of a SQL Server installation?
Database Consistency Checker (DBCC) - Is a statement used to check the logical and physical consistency of a database, check memory usage, decrease the size of a database, check performance statistics, and so on. Database consistency checker (DBCC) ensures the physical and logical consistency of a database, but is not corrective. DBCC can help in repairing or checking the installation in case of any failure.
What is referential integrity and how can we achieve it?
Referential integrity preserves the defined relationships between tables when records are entered or deleted. In SQL Server, referential integrity is based on relationships between foreign keys and primary keys or between foreign keys and unique keys. Referential integrity ensures that key values are consistent across tables. Such consistency requires that there be no references to nonexistent values and that if a key value changes, all references to it change consistently throughout the database.
We can achieve this by using foreign key.
Microsoft .Net Interview Questions 00
How can you deploy an asp.net application ?
You can deploy an ASP.NET Web application using any one of the following three deployment options.
a) Deployment using VS.NET installer
b) Using the Copy Project option in VS .NET
c) XCOPY Deployment
Explain similarities and differences between Java and .NET?
Comparing Java and .NET is comparing apples and oranges. Either the question needs to be to compare Java and C# or J2EE and .NET.
What are the XML files that are important in developing an ASP.NET application?
The XML file necessary for the for developing an asp.net application is Web.config
Specify the best ways to store variables so that we can access them in various pages of ASP.NET application?
Declare the variables in Global.aspx
How many objects are there in ASP?
Answer1
8 objects, they are request,response, server,application,session,file, dictionary, textstream.
Answer2
There are 6 objects in ASP.net
a) Server
b) Session
c) Application
d) ObjectContext
e) Response
f) Request
Which DLL file is needed to be registered for ASP?
The dll needed for the ASP.net is SYSTEM.WEB.dll
Is there any inbuilt paging (for example shoping cart, which will show next 10 records without refreshing) in ASP? How will you do pating?
Use DataGrid control which has in-built paging features for the purpose.
What does Server.MapPath do?
Security Issue
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Answer1
srver.mappath() maps the path given in the argument to the server’s physical path.
Answer2
It returns the complete(absolute) path of the file used in parameter.
Answer3
It returns a string containing the physical path in the server’s file system that corresponds to the virtual or relative path specified by the Path argument.
Name atleast three methods of response object other than Redirect.
Answer1
a) Response.Clear( )
Clears the content of the current output stream.
b) Response.Close( )
Closes the network socket for the current response.
c) Response.End( )
Stops processing the current request and sends all buffered content to the client immediately.
Answer2
methods of Response is Redirect a. Transfer
Name atleast two methods of response object other than Transfer.
a) Response.ClearContent( )
Clears the content of the current output stream.
b) Response.ClearHeaders( )
Clears the HTTP headers from the current output stream.
What is State?
It is the property of the web forms.
ASP.NET provides four types of state:
Application state
Session state
Cookie state
View state.
Explain differences between ADO and DAO.
dao- can access only access database
ado- can access any databases
How many types of cookies are there?
2 types, persistant and impersistant.
How many types of cookies are there?
Answer1
Two type of cookeies.
a) single valued eg request.cookies(”UserName”).value=”Mahesh”
b)Multivalued cookies. These are used in the way collections are used.
e.g.
request.cookies(”CookiName”)(”UserName”)=”Mahesh”
request.cookies(”CookiName”)(”UserID”)=”ABC003?
rember no value method in multivalued cookie
Answer2
There are two types of cookies:
Session cookies
Persistent cookies
Tell few steps for optimizing (for speed and resource) ASP page/application.
Avoid mixing html code with asp code
Which command using Query Analyzer will give you the version of SQL Server and Operating System?
@@VERSION
Returns version, processor architecture, build date, and operating system for the current installation of SQL Server.
How to find the SQL server version from Query Analyzer ?
Answer1
To determine which version of Microsoft SQL Server 2005 is running, connect to SQL Server 2005 by using SQL Server Management Studio, and then run the following Transact-SQL statement:
SELECT SERVERPROPERTY(’productversion’), SERVERPROPERTY (’productlevel’), SERVERPROPERTY (’edition’)
The results are:
• The product version (for example, “9.00.1399.06?)
. • The product level (for example, “RTM”).
• The edition (for example, “Enterprise Edition”).
For example, the result looks similar to:
9.00.1399.06 RTM Enterprise Edition
How to determine which version of SQL Server 2000 is running
To determine which version of SQL Server 2000 is running, connect to SQL Server 2000 by using Query Analyzer, and then run the following code:
SELECT SERVERPROPERTY(’productversion’), SERVERPROPERTY (’productlevel’), SERVERPROPERTY (’edition’)
The results are:
• The product version (for example, 8.00.534).
• The product level (for example, “RTM” or “SP2?).
• The edition (for example, “Standard Edition”). For example, the result looks similar to
:
8.00.534 RTM Standard Edition
Answer2
One can also use SELECT @@Version where the result would look like
Microsoft SQL Server 2005 - 9.00.1399.06 (Intel X86)
Oct 14 2005 00:33:37
Copyright (c) 1988-2005 Microsoft Corporation
Express Edition on Windows NT 5.1 (Build 2600: Service Pack 2)
You can deploy an ASP.NET Web application using any one of the following three deployment options.
a) Deployment using VS.NET installer
b) Using the Copy Project option in VS .NET
c) XCOPY Deployment
Explain similarities and differences between Java and .NET?
Comparing Java and .NET is comparing apples and oranges. Either the question needs to be to compare Java and C# or J2EE and .NET.
What are the XML files that are important in developing an ASP.NET application?
The XML file necessary for the for developing an asp.net application is Web.config
Specify the best ways to store variables so that we can access them in various pages of ASP.NET application?
Declare the variables in Global.aspx
How many objects are there in ASP?
Answer1
8 objects, they are request,response, server,application,session,file, dictionary, textstream.
Answer2
There are 6 objects in ASP.net
a) Server
b) Session
c) Application
d) ObjectContext
e) Response
f) Request
Which DLL file is needed to be registered for ASP?
The dll needed for the ASP.net is SYSTEM.WEB.dll
Is there any inbuilt paging (for example shoping cart, which will show next 10 records without refreshing) in ASP? How will you do pating?
Use DataGrid control which has in-built paging features for the purpose.
What does Server.MapPath do?
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Answer1
srver.mappath() maps the path given in the argument to the server’s physical path.
Answer2
It returns the complete(absolute) path of the file used in parameter.
Answer3
It returns a string containing the physical path in the server’s file system that corresponds to the virtual or relative path specified by the Path argument.
Name atleast three methods of response object other than Redirect.
Answer1
a) Response.Clear( )
Clears the content of the current output stream.
b) Response.Close( )
Closes the network socket for the current response.
c) Response.End( )
Stops processing the current request and sends all buffered content to the client immediately.
Answer2
methods of Response is Redirect a. Transfer
Name atleast two methods of response object other than Transfer.
a) Response.ClearContent( )
Clears the content of the current output stream.
b) Response.ClearHeaders( )
Clears the HTTP headers from the current output stream.
What is State?
It is the property of the web forms.
ASP.NET provides four types of state:
Application state
Session state
Cookie state
View state.
Explain differences between ADO and DAO.
dao- can access only access database
ado- can access any databases
How many types of cookies are there?
2 types, persistant and impersistant.
How many types of cookies are there?
Answer1
Two type of cookeies.
a) single valued eg request.cookies(”UserName”).value=”Mahesh”
b)Multivalued cookies. These are used in the way collections are used.
e.g.
request.cookies(”CookiName”)(”UserName”)=”Mahesh”
request.cookies(”CookiName”)(”UserID”)=”ABC003?
rember no value method in multivalued cookie
Answer2
There are two types of cookies:
Session cookies
Persistent cookies
Tell few steps for optimizing (for speed and resource) ASP page/application.
Avoid mixing html code with asp code
Which command using Query Analyzer will give you the version of SQL Server and Operating System?
@@VERSION
Returns version, processor architecture, build date, and operating system for the current installation of SQL Server.
How to find the SQL server version from Query Analyzer ?
Answer1
To determine which version of Microsoft SQL Server 2005 is running, connect to SQL Server 2005 by using SQL Server Management Studio, and then run the following Transact-SQL statement:
SELECT SERVERPROPERTY(’productversion’), SERVERPROPERTY (’productlevel’), SERVERPROPERTY (’edition’)
The results are:
• The product version (for example, “9.00.1399.06?)
. • The product level (for example, “RTM”).
• The edition (for example, “Enterprise Edition”).
For example, the result looks similar to:
9.00.1399.06 RTM Enterprise Edition
How to determine which version of SQL Server 2000 is running
To determine which version of SQL Server 2000 is running, connect to SQL Server 2000 by using Query Analyzer, and then run the following code:
SELECT SERVERPROPERTY(’productversion’), SERVERPROPERTY (’productlevel’), SERVERPROPERTY (’edition’)
The results are:
• The product version (for example, 8.00.534).
• The product level (for example, “RTM” or “SP2?).
• The edition (for example, “Standard Edition”). For example, the result looks similar to
:
8.00.534 RTM Standard Edition
Answer2
One can also use SELECT @@Version where the result would look like
Microsoft SQL Server 2005 - 9.00.1399.06 (Intel X86)
Oct 14 2005 00:33:37
Copyright (c) 1988-2005 Microsoft Corporation
Express Edition on Windows NT 5.1 (Build 2600: Service Pack 2)
.Net Database Interview Questions and Answers free
To test a Web Service you must create a windows application or web application to consume this service? It is True/False?
FALSE
How many classes can a single.NET DLL contain?
Answer1:
As many
Answer2:
One or more
What are good ADO.NET object(s) to replace the ADO Recordset object?
The differences includes
In ADO, the in-memory representation of data is the Recordset.
In ADO.net, it is the dataset
A recordset looks like a single table in ADO
In contrast, a dataset is a collection of one or more tables in ADO.net
ADO is designed primarily for connected access
ADO.net the disconnected access to the database is used
In ADO you communicate with the database by making calls to an OLE DB provider.
In ADO.NET you communicate with the database through a data adapter (an OleDbDataAdapter, SqlDataAdapter, OdbcDataAdapter, or OracleDataAdapter object), which makes calls to an OLE DB provider or the APIs provided by the underlying data source.
In ADO you cant update the database from the recordset. ADO.NET the data adapter allows you to control how the changes to the dataset are transmitted to the database.
On order to get assembly info which namespace we should import?
System.Reflection Namespace
How do you declare a static variable and what is its lifetime? Give an example.
Answer1
static int Myint–The life time is during the entire application.
br> Answer2
The static modifier is used to declare a static member, which belongs to the type itself rather than to a specific object. The static modifier can be used with fields, methods, properties, operators, events and constructors, but cannot be used with indexers, destructors, or types. In C#, the static keyword indicates a class variable. In VB, the equivalent keyword is Shared. Its scoped to the class in which it occurs.
Example
a. Static int var //in c#.net
b. static void Time( ) //in c#.net
How do you get records number from 5 to 15 in a dataset of 100 records? Write code.
Answer1
DataSet ds1=new DataSet(); String strCon=”data source=IBM-6BC8A0DACEF;initial catalog=pubs;integrated security=SSPI;persist” +” security info=False;user
id=sa;workstation id=IBM-6BC8A0DACEF;packet size=4096?;
Security Tip
Use Firefox instead of Internet Explorer and PREVENT Spyware !
Firefox is free and is considered the best free, safe web browser available today
Browse the web faster. Get Firefox with Google Toolbar
String strCom1=”SELECT * FROM employee”;
SqlDataAdapter sqlDa1=new SqlDataAdapter(strCom1,strCon);
ds1.Tables.Add(”employee”);
sqlDa1.Fill(ds1,40,50,ds1.Tables[”employee”].TableName);
DataGrid dg1.DataSource=ds1.Tables[”employee”].DefaultView;
dg1.DataBind();
Answer2
OleDbConnection1.Open()
OleDbDataAdapter1.Fill(DataSet21, 5, 15, “tab”)
This will fill the dataset with the records starting at 5 to 15
How do you call and execute a Stored Procedure in .NET? Give an example.
Answer1
ds1=new DataSet();
sqlCon1=new SqlConnection(connectionstring);
String strCom1=”byroyalty”;
sqlCom1=new SqlCommand(strCom1,sqlCon1);
sqlCom1.CommandType=CommandType.StoredProcedure;
sqlDa1=new SqlDataAdapter(sqlCom1);
SqlParameter myPar=new SqlParameter(”@percentage”,SqlDbType.Int);
sqlCom1.Parameters.Add (myPar);
myPar.Value=40;
sqlDa1.Fill(ds1);
dg1.DataSource=ds1;
dg1.DataBind();
Answer2
Yes
Dim cn as new OleDbConnection ( “Provider=Microsoft.Jet.OLEDB.4.0;”+ _
“Data Source=C:\Documents and Settings\User\My Documents\Visual Studio Projects\1209\db1.mdb”+ _
“User ID=Admin;”+ _
“Password=;”);
Dim cmd As New OleDbCommand(”Products”, cn)
cmd.CommandType = CommandType.StoredProcedure
Dim da As New OleDataAdapter(cmd)
Dim ds As New DataSet()
da.Fill(ds, “Products”)
DataGrid1.DataSource = ds.Tables(”Products”)
What is the maximum length of a varchar in SQL Server?
Answer1
VARCHAR[(n)]
Null-terminated Unicode character string of length n,
with a maximum of 255 characters. If n is not supplied, then 1 is assumed.
Answer2
8000
Answer3
The business logic is the aspx.cs or the aspx.vb where the code is being written. The presentation logic is done with .aspx extention.
How do you define an integer in SQL Server?
We define integer in Sql server as
var_name int
How do you separate business logic while creating an ASP.NET application?
There are two level of asp.net debugging
1. Page level debugging
For this we have to edit the page level debugging enable the trace to true in the line in the html format of the page.
%@ Page Language=”vb” trace=”true”AutoEventWireup=”false” Codebehind=”WebForm1.aspx.vb” Inherits=”WebApplication2.WebForm1?>
2. You can enable the debugging in the application level for this
Edit the following trace value in web.config file
Enable trace enabled=true.
If there is a calendar control to be included in each page of your application, and and we do not intend to use the Microsoft-provided calendar control, how do you develop it? Do you copy and paste the code into each and every page of your application?
Create the Calendar User Control
The control we will create will contain a calendar control and a label which has the corresponding date and time written
Steps are:-
Creating a CalenderControl
1) To begin, open Visual Studio .NET and begin a new C# Windows Control Library.
2) You may name it whatever you like, for this sample the project name will be CalenderControl
Using the Calender Control in a Windows Application
It’s just like adding any other control like a button or a label.
1) First, create a new Windows Application project named: CustomControl.
2) Add a reference to the Calender Control DLL named: CalenderControl.dll.
3) Now you a can customize the Toolbox:
Right-Click the Toolbox> .NET Framework Components> Browse> select the CalenderControl.dll.
4)The Calender Control is now added to the Toolbox and can be inserted in Windows Form as any other control. The control itself will take care of the date display
FALSE
How many classes can a single.NET DLL contain?
Answer1:
As many
Answer2:
One or more
What are good ADO.NET object(s) to replace the ADO Recordset object?
The differences includes
In ADO, the in-memory representation of data is the Recordset.
In ADO.net, it is the dataset
A recordset looks like a single table in ADO
In contrast, a dataset is a collection of one or more tables in ADO.net
ADO is designed primarily for connected access
ADO.net the disconnected access to the database is used
In ADO you communicate with the database by making calls to an OLE DB provider.
In ADO.NET you communicate with the database through a data adapter (an OleDbDataAdapter, SqlDataAdapter, OdbcDataAdapter, or OracleDataAdapter object), which makes calls to an OLE DB provider or the APIs provided by the underlying data source.
In ADO you cant update the database from the recordset. ADO.NET the data adapter allows you to control how the changes to the dataset are transmitted to the database.
On order to get assembly info which namespace we should import?
System.Reflection Namespace
How do you declare a static variable and what is its lifetime? Give an example.
Answer1
static int Myint–The life time is during the entire application.
br> Answer2
The static modifier is used to declare a static member, which belongs to the type itself rather than to a specific object. The static modifier can be used with fields, methods, properties, operators, events and constructors, but cannot be used with indexers, destructors, or types. In C#, the static keyword indicates a class variable. In VB, the equivalent keyword is Shared. Its scoped to the class in which it occurs.
Example
a. Static int var //in c#.net
b. static void Time( ) //in c#.net
How do you get records number from 5 to 15 in a dataset of 100 records? Write code.
Answer1
DataSet ds1=new DataSet(); String strCon=”data source=IBM-6BC8A0DACEF;initial catalog=pubs;integrated security=SSPI;persist” +” security info=False;user
id=sa;workstation id=IBM-6BC8A0DACEF;packet size=4096?;
Security Tip
Use Firefox instead of Internet Explorer and PREVENT Spyware !
Firefox is free and is considered the best free, safe web browser available today
Browse the web faster. Get Firefox with Google Toolbar
String strCom1=”SELECT * FROM employee”;
SqlDataAdapter sqlDa1=new SqlDataAdapter(strCom1,strCon);
ds1.Tables.Add(”employee”);
sqlDa1.Fill(ds1,40,50,ds1.Tables[”employee”].TableName);
DataGrid dg1.DataSource=ds1.Tables[”employee”].DefaultView;
dg1.DataBind();
Answer2
OleDbConnection1.Open()
OleDbDataAdapter1.Fill(DataSet21, 5, 15, “tab”)
This will fill the dataset with the records starting at 5 to 15
How do you call and execute a Stored Procedure in .NET? Give an example.
Answer1
ds1=new DataSet();
sqlCon1=new SqlConnection(connectionstring);
String strCom1=”byroyalty”;
sqlCom1=new SqlCommand(strCom1,sqlCon1);
sqlCom1.CommandType=CommandType.StoredProcedure;
sqlDa1=new SqlDataAdapter(sqlCom1);
SqlParameter myPar=new SqlParameter(”@percentage”,SqlDbType.Int);
sqlCom1.Parameters.Add (myPar);
myPar.Value=40;
sqlDa1.Fill(ds1);
dg1.DataSource=ds1;
dg1.DataBind();
Answer2
Yes
Dim cn as new OleDbConnection ( “Provider=Microsoft.Jet.OLEDB.4.0;”+ _
“Data Source=C:\Documents and Settings\User\My Documents\Visual Studio Projects\1209\db1.mdb”+ _
“User ID=Admin;”+ _
“Password=;”);
Dim cmd As New OleDbCommand(”Products”, cn)
cmd.CommandType = CommandType.StoredProcedure
Dim da As New OleDataAdapter(cmd)
Dim ds As New DataSet()
da.Fill(ds, “Products”)
DataGrid1.DataSource = ds.Tables(”Products”)
What is the maximum length of a varchar in SQL Server?
Answer1
VARCHAR[(n)]
Null-terminated Unicode character string of length n,
with a maximum of 255 characters. If n is not supplied, then 1 is assumed.
Answer2
8000
Answer3
The business logic is the aspx.cs or the aspx.vb where the code is being written. The presentation logic is done with .aspx extention.
How do you define an integer in SQL Server?
We define integer in Sql server as
var_name int
How do you separate business logic while creating an ASP.NET application?
There are two level of asp.net debugging
1. Page level debugging
For this we have to edit the page level debugging enable the trace to true in the line in the html format of the page.
%@ Page Language=”vb” trace=”true”AutoEventWireup=”false” Codebehind=”WebForm1.aspx.vb” Inherits=”WebApplication2.WebForm1?>
2. You can enable the debugging in the application level for this
Edit the following trace value in web.config file
Enable trace enabled=true.
If there is a calendar control to be included in each page of your application, and and we do not intend to use the Microsoft-provided calendar control, how do you develop it? Do you copy and paste the code into each and every page of your application?
Create the Calendar User Control
The control we will create will contain a calendar control and a label which has the corresponding date and time written
Steps are:-
Creating a CalenderControl
1) To begin, open Visual Studio .NET and begin a new C# Windows Control Library.
2) You may name it whatever you like, for this sample the project name will be CalenderControl
Using the Calender Control in a Windows Application
It’s just like adding any other control like a button or a label.
1) First, create a new Windows Application project named: CustomControl.
2) Add a reference to the Calender Control DLL named: CalenderControl.dll.
3) Now you a can customize the Toolbox:
Right-Click the Toolbox> .NET Framework Components> Browse> select the CalenderControl.dll.
4)The Calender Control is now added to the Toolbox and can be inserted in Windows Form as any other control. The control itself will take care of the date display
What are different methods of session maintenance in ASP.NET?
What are different methods of session maintenance in ASP.NET?
3 types:
In-process storage.
Session State Service.
Microsoft SQL Server.
In-Process Storage
The default location for session state storage is in the ASP.NET process itself.
Session State Service
As an alternative to using in-process storage for session state, ASP.NET provides the ASP.NET State Service. The State Service gives you an out-of-process alternative for storing session state that is not tied quite so closely to ASP. Net's own process.
To use the State Service, you need to edit the sessionState element in your ASP.NET application’s web.config file:
You’ll also need to start the ASP.NET State Service on the computer that you specified in the stateConnectionString attribute. The .NET Framework installs this service, but by default it’s set to manual startup. If you’re going to depend on it for storing session state, you’ll want to change that to automatic startup by using the Services MMC plug-in in the Administrative Tools group.
If you make these changes, and then repeat the previous set of steps, you’ll see slightly different behavior: session state persists even if you recycle the ASP.NET process.
There are two main advantages to using the State Service. First, it is not running in the same process as ASP.NET, so a crash of ASP.NET will not destroy session information. Second, the stateConnectionString that’s used to locate the State Service includes the TCP/IP address of the service, which need not be running on the same computer as ASP.NET. This allows you to share state information across a web garden (multiple processors on the same computer) or even across a web farm (multiple servers running the application). With the default in-process storage, you can’t share state information between multiple instances of your application.
The major disadvantage of using the State Service is that it’s an external process, rather than part of ASP.NET. That means that reading and writing session state is slower than it would be if you kept the state in-process. And, of course, it’s one more process that you need to manage. As an example of the extra effort that this can entail, there is a bug in the initial release of the State Service that allows a determined attacker to crash the ASP.NET process remotely. If you’re using the State Service to store session state, you should install the patch from Microsoft Security Bulletin MS02-66, or install SP2 for the .NET Framework.
Microsoft SQL Server
The final choice for storing state information is to save it in a Microsoft SQL Server database. To use SQL Server for storing session state, you need to perform several setup steps:
Run the InstallSqlState.sql script on the Microsoft SQL Server where you intend to store session state. This script will create the necessary database and database objects. The .NET Framework installs this script in the same folder as its compilers and other tools–for example, C:\WINNT\Microsoft.NET\Framework\v1.0.3705 on a Windows 2000 computer with the 1.0 version of the Framework. Edit the sessionState element in the web.config file for your ASP.NET application as follows:
Supply the server name, user name, and password for a SQL Server account that has access to the session state database in the sqlConnectionString attribute.
Like the State Service, SQL Server lets you share session state among the processors in a web garden or the servers in a web farm. But you also get the additional benefit of persistent storage. Even if the computer hosting SQL Server crashes and is restarted, the session state information will still be present in the database, and will be available as soon as the database is running again. That’s because SQL Server, being an industrial-strength database, is designed to log its operations and protect your data at (almost) all costs. If you’re willing to invest in SQL Server clustering, you can keep the session state data available transparently to ASP.NET even if the primary SQL Server computer crashes.
Like the State Service, SQL Server is slower than keeping session state in process. You also need to pay additional licensing fees to use SQL Server for session state in a production application. And, of course, you need to worry about SQL Server-specific threats such as the “Slammer” worm.
What is Viewstate?
A server control’s view state is the accumulation of all its property values. In order to preserve these values across HTTP requests, ASP.NET server controls use this property, which is an instance of the StateBag class, to store the property values.
Can any object be stored in a Viewstate?
An object that either is serializable or has a TypeConverter defined for it can be persisted in ViewState
What should you do to store an object in a Viewstate?
Do serialization of convert the object to string
Explain how Viewstate is being formed and how it’s stored on client.
The type of ViewState is System.Web.UI.StateBag, which is a dictionary that stores name/value pairs. ViewState is persisted to a string variable by the ASP.NET page framework and sent to the client and back as a hidden variable. Upon postback, the page framework parses the input string from the hidden variable and populates the ViewState property of each control. If a control uses ViewState for property data instead of a private field, that property automatically will be persisted across round trips to the client. (If a property is not persisted in ViewState, it is good practice to return its default value on postback.)
What do you know about ADO.NET’s objects and methods?
ADO.NET provides consistent access to data sources such as Microsoft SQL Server, as well as data sources exposed through OLE DB and XML.
Data-sharing consumer applications can use ADO.NET to connect to these different data sources and retrieve, manipulate, and update data.
ADO.NET provides first-class support for the disconnected, n-tier programming environment for which many new applications are written.
Explain DataSet.AcceptChanges and DataAdapter.Update methods.
DataAdapter.Update method Calls the respective INSERT, UPDATE, or DELETE statements for each inserted, updated, or deleted row in the DataSet.
DataSet.AcceptChanges method Commits all the changes made to this row since the last time AcceptChanges was called.
When we go for html server controls and when we go for web server controls?
Server controls are a part of ASP.net. When a server control is used there will be an extra overhead on the server to create the control at runtime and accordingly set the values. HTML controls are static controls and are easy to use. They are supported is ASP.net.
As a rule, if there is a corresponding HTML control available instead of the server control, you should always go for the HTML control as it enhances the server performance and ensures faster response. Server controls should be used when it is found that the available HTML controls are not sufficient to achieve the task.
3 types:
In-process storage.
Session State Service.
Microsoft SQL Server.
In-Process Storage
The default location for session state storage is in the ASP.NET process itself.
Session State Service
As an alternative to using in-process storage for session state, ASP.NET provides the ASP.NET State Service. The State Service gives you an out-of-process alternative for storing session state that is not tied quite so closely to ASP. Net's own process.
To use the State Service, you need to edit the sessionState element in your ASP.NET application’s web.config file:
You’ll also need to start the ASP.NET State Service on the computer that you specified in the stateConnectionString attribute. The .NET Framework installs this service, but by default it’s set to manual startup. If you’re going to depend on it for storing session state, you’ll want to change that to automatic startup by using the Services MMC plug-in in the Administrative Tools group.
If you make these changes, and then repeat the previous set of steps, you’ll see slightly different behavior: session state persists even if you recycle the ASP.NET process.
There are two main advantages to using the State Service. First, it is not running in the same process as ASP.NET, so a crash of ASP.NET will not destroy session information. Second, the stateConnectionString that’s used to locate the State Service includes the TCP/IP address of the service, which need not be running on the same computer as ASP.NET. This allows you to share state information across a web garden (multiple processors on the same computer) or even across a web farm (multiple servers running the application). With the default in-process storage, you can’t share state information between multiple instances of your application.
The major disadvantage of using the State Service is that it’s an external process, rather than part of ASP.NET. That means that reading and writing session state is slower than it would be if you kept the state in-process. And, of course, it’s one more process that you need to manage. As an example of the extra effort that this can entail, there is a bug in the initial release of the State Service that allows a determined attacker to crash the ASP.NET process remotely. If you’re using the State Service to store session state, you should install the patch from Microsoft Security Bulletin MS02-66, or install SP2 for the .NET Framework.
Microsoft SQL Server
The final choice for storing state information is to save it in a Microsoft SQL Server database. To use SQL Server for storing session state, you need to perform several setup steps:
Run the InstallSqlState.sql script on the Microsoft SQL Server where you intend to store session state. This script will create the necessary database and database objects. The .NET Framework installs this script in the same folder as its compilers and other tools–for example, C:\WINNT\Microsoft.NET\Framework\v1.0.3705 on a Windows 2000 computer with the 1.0 version of the Framework. Edit the sessionState element in the web.config file for your ASP.NET application as follows:
Supply the server name, user name, and password for a SQL Server account that has access to the session state database in the sqlConnectionString attribute.
Like the State Service, SQL Server lets you share session state among the processors in a web garden or the servers in a web farm. But you also get the additional benefit of persistent storage. Even if the computer hosting SQL Server crashes and is restarted, the session state information will still be present in the database, and will be available as soon as the database is running again. That’s because SQL Server, being an industrial-strength database, is designed to log its operations and protect your data at (almost) all costs. If you’re willing to invest in SQL Server clustering, you can keep the session state data available transparently to ASP.NET even if the primary SQL Server computer crashes.
Like the State Service, SQL Server is slower than keeping session state in process. You also need to pay additional licensing fees to use SQL Server for session state in a production application. And, of course, you need to worry about SQL Server-specific threats such as the “Slammer” worm.
What is Viewstate?
A server control’s view state is the accumulation of all its property values. In order to preserve these values across HTTP requests, ASP.NET server controls use this property, which is an instance of the StateBag class, to store the property values.
Can any object be stored in a Viewstate?
An object that either is serializable or has a TypeConverter defined for it can be persisted in ViewState
What should you do to store an object in a Viewstate?
Do serialization of convert the object to string
Explain how Viewstate is being formed and how it’s stored on client.
The type of ViewState is System.Web.UI.StateBag, which is a dictionary that stores name/value pairs. ViewState is persisted to a string variable by the ASP.NET page framework and sent to the client and back as a hidden variable. Upon postback, the page framework parses the input string from the hidden variable and populates the ViewState property of each control. If a control uses ViewState for property data instead of a private field, that property automatically will be persisted across round trips to the client. (If a property is not persisted in ViewState, it is good practice to return its default value on postback.)
What do you know about ADO.NET’s objects and methods?
ADO.NET provides consistent access to data sources such as Microsoft SQL Server, as well as data sources exposed through OLE DB and XML.
Data-sharing consumer applications can use ADO.NET to connect to these different data sources and retrieve, manipulate, and update data.
ADO.NET provides first-class support for the disconnected, n-tier programming environment for which many new applications are written.
Explain DataSet.AcceptChanges and DataAdapter.Update methods.
DataAdapter.Update method Calls the respective INSERT, UPDATE, or DELETE statements for each inserted, updated, or deleted row in the DataSet.
DataSet.AcceptChanges method Commits all the changes made to this row since the last time AcceptChanges was called.
When we go for html server controls and when we go for web server controls?
Server controls are a part of ASP.net. When a server control is used there will be an extra overhead on the server to create the control at runtime and accordingly set the values. HTML controls are static controls and are easy to use. They are supported is ASP.net.
As a rule, if there is a corresponding HTML control available instead of the server control, you should always go for the HTML control as it enhances the server performance and ensures faster response. Server controls should be used when it is found that the available HTML controls are not sufficient to achieve the task.
Microsoft .Net Interview Questions and Answers 8
What is the Differnce Between Response.write & response.output.Write
In ASP.NET the Response object is of type HttpResponse and when you say Response.Write you’re really saying (basically) HttpContext.Current.Response.Write and calling one of the many overloaded Write methods of HttpResponse.
Response.Write then calls .Write() on it’s internal TextWriter object:
public void Write(object obj){ this._writer.Write(obj);}
HttpResponse also has a Property called Output that is of type, yes, TextWriter, so:
public TextWriter get_Output(){ return this._writer; }
Which means you can to the Response whatever a TextWriter will let you. Now, TextWriters support a Write() method ala String.Format, so you can do this:
Response.Output.Write(”Scott is {0} at {1:d}”, “cool”,DateTime.Now);
But internally, of course, this this is happening:
public virtual void Write(string format, params object[] arg)
{
this.Write(string.Format(format, arg));
}
Which dll is required to translate XML to SQL in IIS ?
Microsoft.data.sqlxml.dll
What is an interface and what is an abstract class? Please, expand by examples of using both. Explain why.
Answers1:
In a interface class, all methods are abstract without implementation where as in an abstract class some methods we can define concrete. In interface, no accessibility modifiers are allowed. An abstract class may have accessibility modifiers. Interface and abstract class are basically a set of rules which u have to follow in case u r using them(inheriting them).
Answers2:
Abstract classes are closely related to interfaces. They are classes that cannot be instantiated, and are frequently either partially implemented, or not at all implemented. One key difference between abstract classes and interfaces is that a class may implement an unlimited number of interfaces, but may inherit from only one abstract (or any other kind of) class. A class that is derived from an abstract class may still implement interfaces. Abstract classes are useful when creating components because they allow you specify an invariant level of functionality in some methods, but leave the implementation of other methods until a specific implementation of that class is needed. They also version well, because if additional functionality is needed in derived classes, it can be added to the base class without breaking code.
Answers3:
Abstract Classes
An abstract class is the one that is not used to create objects. An abstract class is designed to act as a base class (to be inherited by other classes). Abstract class is a design concept in program development and provides a base upon which other classes are built. Abstract classes are similar to interfaces. After declaring an abstract class, it cannot be instantiated on it’s own, it must be inherited. Like interfaces, abstract classes can specify members that must be implemented in inheriting classes. Unlike interfaces, a class can inherit only one abstract class. Abstract classes can only specify members that should be implemented by all inheriting classes.
Answers4:
An interface looks like a class, but has no implementation. They’re great for putting together plug-n-play like architectures where components can be interchanged at will. Think Firefox Plug-in extension implementation. If you need to change your design, make it an interface. However, you may have abstract classes that provide some default behavior. Abstract classes are excellent candidates inside of application frameworks.
Answers5:
One additional key difference between interfaces and abstract classes (possibly the most important one) is that multiple interfaces can be implemented by a class, but only one abstract class can be inherited by any single class.
Some background on this: C++ supports multiple inheritance, but C# does not. Multiple inheritance in C++ has always be controversial, because the resolution of multiple inherited implementations of the same method from different base classes is hard to control and anticipate. C# decided to avoid this problem by allowing a class to implement multiple interfaces, which do not contain method implementations, but restricting a class to have at most a single parent class. Although this can result in redundant implementations of the same method when different classes implement the same interface, it is still an excellent compromise.
Another difference between interfaces and abstract classes is that an interface can be implemented by an abstract class, but no class, abstract or otherwise, can be inherited by an interface.
Answers6:
What is an Abstract class?
An abstract class is a special kind of class that cannot be instantiated. So the question is why we need a class that cannot be instantiated? An abstract class is only to be sub-classed (inherited from). In other words, it only allows other classes to inherit from it but cannot be instantiated. The advantage is that it enforces certain hierarchies for all the subclasses. In simple words, it is a kind of contract that forces all the subclasses to carry on the same hierarchies or standards.
What is an Interface?
An interface is not a class. It is an entity that is defined by the word Interface. An interface has no implementation; it only has the signature or in other words, just the definition of the methods without the body. As one of the similarities to Abstract class, it is a contract that is used to define hierarchies for all subclasses or it defines specific set of methods and their arguments. The main difference between them is that a class can implement more than one interface but can only inherit from one abstract class. Since C# doesn’t support multiple inheritance, interfaces are used to implement multiple inheritance.
What is serialization, how it works in .NET?
Serialization is when you persist the state of an object to a storage medium so an exact copy can be re-created at a later stage.
Serialization is used to save session state in ASP.NET.
Serialization is to copy objects to the Clipboard in Windows Forms
Serialization is used by remoting to pass objects by value from one application domain to another
What should one do to make class serializable?
Answers1:
To make a class serializable is to mark it with the Serializable attribute as follows.
[Serializable]
public class MyObject {
public int n1 = 0;
public int n2 = 0;
public String str = null;
}
What exactly is being serialized when you perform serialization?
The object’s state (values)
How does output caching work in ASP.NET?
Output caching is a powerful technique that increases request/response throughput by caching the content generated from dynamic pages. Output caching is enabled by default, but output from any given response is not cached unless explicit action is taken to make the response cacheable.
To make a response eligible for output caching, it must have a valid expiration/validation policy and public cache visibility. This can be done using either the low-level OutputCache API or the high-level @ OutputCache directive. When output caching is enabled, an output cache entry is created on the first GET request to the page. Subsequent GET or HEAD requests are served from the output cache entry until the cached request expires.
The output cache also supports variations of cached GET or POST name/value pairs.
The output cache respects the expiration and validation policies for pages. If a page is in the output cache and has been marked with an expiration policy that indicates that the page expires 60 minutes from the time it is cached, the page is removed from the output cache after 60 minutes. If another request is received after that time, the page code is executed and the page can be cached again. This type of expiration policy is called absolute expiration - a page is valid until a certain time.
What is connection pooling and how do you make your application use it?
Opening database connection is a time consuming operation.
Connection pooling increases the performance of the applications by reusing the active database connections instead of create new connection for every request.
Connection pooling Behaviour is controlled by the connection string parameters.
Follwing the the 4 parameters that control most of the connection pooling behaviour.
1. Connect Timeout
2. Max Pool Size
3. Min Pool Size
4. Pooling
In ASP.NET the Response object is of type HttpResponse and when you say Response.Write you’re really saying (basically) HttpContext.Current.Response.Write and calling one of the many overloaded Write methods of HttpResponse.
Response.Write then calls .Write() on it’s internal TextWriter object:
public void Write(object obj){ this._writer.Write(obj);}
HttpResponse also has a Property called Output that is of type, yes, TextWriter, so:
public TextWriter get_Output(){ return this._writer; }
Which means you can to the Response whatever a TextWriter will let you. Now, TextWriters support a Write() method ala String.Format, so you can do this:
Response.Output.Write(”Scott is {0} at {1:d}”, “cool”,DateTime.Now);
But internally, of course, this this is happening:
public virtual void Write(string format, params object[] arg)
{
this.Write(string.Format(format, arg));
}
Which dll is required to translate XML to SQL in IIS ?
Microsoft.data.sqlxml.dll
What is an interface and what is an abstract class? Please, expand by examples of using both. Explain why.
Answers1:
In a interface class, all methods are abstract without implementation where as in an abstract class some methods we can define concrete. In interface, no accessibility modifiers are allowed. An abstract class may have accessibility modifiers. Interface and abstract class are basically a set of rules which u have to follow in case u r using them(inheriting them).
Answers2:
Abstract classes are closely related to interfaces. They are classes that cannot be instantiated, and are frequently either partially implemented, or not at all implemented. One key difference between abstract classes and interfaces is that a class may implement an unlimited number of interfaces, but may inherit from only one abstract (or any other kind of) class. A class that is derived from an abstract class may still implement interfaces. Abstract classes are useful when creating components because they allow you specify an invariant level of functionality in some methods, but leave the implementation of other methods until a specific implementation of that class is needed. They also version well, because if additional functionality is needed in derived classes, it can be added to the base class without breaking code.
Answers3:
Abstract Classes
An abstract class is the one that is not used to create objects. An abstract class is designed to act as a base class (to be inherited by other classes). Abstract class is a design concept in program development and provides a base upon which other classes are built. Abstract classes are similar to interfaces. After declaring an abstract class, it cannot be instantiated on it’s own, it must be inherited. Like interfaces, abstract classes can specify members that must be implemented in inheriting classes. Unlike interfaces, a class can inherit only one abstract class. Abstract classes can only specify members that should be implemented by all inheriting classes.
Answers4:
An interface looks like a class, but has no implementation. They’re great for putting together plug-n-play like architectures where components can be interchanged at will. Think Firefox Plug-in extension implementation. If you need to change your design, make it an interface. However, you may have abstract classes that provide some default behavior. Abstract classes are excellent candidates inside of application frameworks.
Answers5:
One additional key difference between interfaces and abstract classes (possibly the most important one) is that multiple interfaces can be implemented by a class, but only one abstract class can be inherited by any single class.
Some background on this: C++ supports multiple inheritance, but C# does not. Multiple inheritance in C++ has always be controversial, because the resolution of multiple inherited implementations of the same method from different base classes is hard to control and anticipate. C# decided to avoid this problem by allowing a class to implement multiple interfaces, which do not contain method implementations, but restricting a class to have at most a single parent class. Although this can result in redundant implementations of the same method when different classes implement the same interface, it is still an excellent compromise.
Another difference between interfaces and abstract classes is that an interface can be implemented by an abstract class, but no class, abstract or otherwise, can be inherited by an interface.
Answers6:
What is an Abstract class?
An abstract class is a special kind of class that cannot be instantiated. So the question is why we need a class that cannot be instantiated? An abstract class is only to be sub-classed (inherited from). In other words, it only allows other classes to inherit from it but cannot be instantiated. The advantage is that it enforces certain hierarchies for all the subclasses. In simple words, it is a kind of contract that forces all the subclasses to carry on the same hierarchies or standards.
What is an Interface?
An interface is not a class. It is an entity that is defined by the word Interface. An interface has no implementation; it only has the signature or in other words, just the definition of the methods without the body. As one of the similarities to Abstract class, it is a contract that is used to define hierarchies for all subclasses or it defines specific set of methods and their arguments. The main difference between them is that a class can implement more than one interface but can only inherit from one abstract class. Since C# doesn’t support multiple inheritance, interfaces are used to implement multiple inheritance.
What is serialization, how it works in .NET?
Serialization is when you persist the state of an object to a storage medium so an exact copy can be re-created at a later stage.
Serialization is used to save session state in ASP.NET.
Serialization is to copy objects to the Clipboard in Windows Forms
Serialization is used by remoting to pass objects by value from one application domain to another
What should one do to make class serializable?
Answers1:
To make a class serializable is to mark it with the Serializable attribute as follows.
[Serializable]
public class MyObject {
public int n1 = 0;
public int n2 = 0;
public String str = null;
}
What exactly is being serialized when you perform serialization?
The object’s state (values)
How does output caching work in ASP.NET?
Output caching is a powerful technique that increases request/response throughput by caching the content generated from dynamic pages. Output caching is enabled by default, but output from any given response is not cached unless explicit action is taken to make the response cacheable.
To make a response eligible for output caching, it must have a valid expiration/validation policy and public cache visibility. This can be done using either the low-level OutputCache API or the high-level @ OutputCache directive. When output caching is enabled, an output cache entry is created on the first GET request to the page. Subsequent GET or HEAD requests are served from the output cache entry until the cached request expires.
The output cache also supports variations of cached GET or POST name/value pairs.
The output cache respects the expiration and validation policies for pages. If a page is in the output cache and has been marked with an expiration policy that indicates that the page expires 60 minutes from the time it is cached, the page is removed from the output cache after 60 minutes. If another request is received after that time, the page code is executed and the page can be cached again. This type of expiration policy is called absolute expiration - a page is valid until a certain time.
What is connection pooling and how do you make your application use it?
Opening database connection is a time consuming operation.
Connection pooling increases the performance of the applications by reusing the active database connections instead of create new connection for every request.
Connection pooling Behaviour is controlled by the connection string parameters.
Follwing the the 4 parameters that control most of the connection pooling behaviour.
1. Connect Timeout
2. Max Pool Size
3. Min Pool Size
4. Pooling
Microsoft .Net Interview Questions and Answers 2
What are the advantages and drawbacks of using ADO.NET?
Pros
====
ADO.NET is rich with plenty of features that are bound to impress even the most skeptical of programmers. If this weren’t the case, Microsoft wouldn’t even be able to get anyone to use the Beta. What we’ve done here is come up with a short list of some of the more outstanding benefits to using the ADO.NET architecture and the System.Data namespace.
* Performance – there is no doubt that ADO.NET is extremely fast. The actual figures vary depending on who performed the test and which benchmark was being used, but ADO.NET performs much, much faster at the same tasks than its predecessor, ADO. Some of the reasons why ADO.NET is faster than ADO are discussed in the ADO versus ADO.NET section later in this chapter.
* Optimized SQL Provider – in addition to performing well under general circumstances, ADO.NET includes a SQL Server Data Provider that is highly optimized for interaction with SQL Server. It uses SQL Server’s own TDS (Tabular Data Stream) format for exchanging information. Without question, your SQL Server 7 and above data access operations will run blazingly fast utilizing this optimized Data Provider.
* XML Support (and Reliance) – everything you do in ADO.NET at some point will boil down to the use of XML. In fact, many of the classes in ADO.NET, such as the DataSet, are so intertwined with XML that they simply cannot exist or function without utilizing the technology. You’ll see later when we compare and contrast the “old” and the “new” why the reliance on XML for internal storage provides many, many advantages, both to the framework and to the programmer utilizing the class library.
* Disconnected Operation Model – the core ADO.NET class, the DataSet, operates in an entirely disconnected fashion. This may be new to some programmers, but it is a remarkably efficient and scalable architecture. Because the disconnected model allows for the DataSet class to be unaware of the origin of its data, an unlimited number of supported data sources can be plugged into code without any hassle in the future.
* Rich Object Model – the entire ADO.NET architecture is built on a hierarchy of class inheritance and interface implementation. Once you start looking for things you need within this namespace, you’ll find that the logical inheritance of features and base class support makes the entire system extremely easy to use, and very customizable to suit your own needs. It is just another example of how everything in the .NET framework is pushing toward a trend of strong application design and strong OOP implementations.
Cons
====
Hard as it may be to believe, there are a couple of drawbacks or disadvantages to using the ADO.NET architecture. I’m sure others can find many more faults than we list here, but we decided to stick with a short list of some of the more obvious and important shortcomings of the technology.
* Managed-Only Access – for a few obvious reasons, and some far more technical, you cannot utilize the ADO.NET architecture from anything but managed code. This means that there is no COM interoperability allowed for ADO.NET. Therefore, in order to take advantage of the advanced SQL Server Data Provider and any other feature like DataSets, XML internal data storage, etc, your code must be running under the CLR.
* Only Three Managed Data Providers (so far) – unfortunately, if you need to access any data that requires a driver that cannot be used through either an OLEDB provider or the SQL Server Data Provider, then you may be out of luck. However, the good news is that the OLEDB provider for ODBC is available for download from Microsoft. At that point the down-side becomes one of performance, in which you are invoking multiple layers of abstraction as well as crossing the COM InterOp gap, incurring some initial overhead as well.
* Learning Curve – despite the misleading name, ADO.NET is not simply a new version of ADO, nor should it even be considered a direct successor. ADO.NET should be thought of more as the data access class library for use with the .NET framework. The difficulty in learning to use ADO.NET to its fullest is that a lot of it does seem familiar. It is this that causes some common pitfalls. Programmers need to learn that even though some syntax may appear the same, there is actually a considerable amount of difference in the internal workings of many classes. For example (this will be discussed in far more detail later), an ADO.NET DataSet is nothing at all like a disconnected ADO RecordSet. Some may consider a learning curve a drawback, but I consider learning curves more like scheduling issues. There’s a learning curve in learning anything new; it’s just up to you to schedule that curve into your time so that you can learn the new technology at a pace that fits your schedule.
Why The JavaScript Validation Not Run on the Asp.Net Button But Run SuccessFully On The HTML Button
The Asp.Net Button Is post backed on the server & not yet Submit & when It goes to the server its states is lost So if we r using javascript in our application so we always use the Input Button in the asp Button
what is the difference between user control an custom control? advantages/disadvantages?
Web user controls Vs Web custom controls
Easier to create Vs Harder to create
Limited support for consumers who use a visual design tool Vs Full visual design tool support for consumers
A separate copy of the control is required in each application Vs Only a single copy of the control is required, in the global assembly cache
Cannot be added to the Toolbox in Visual Studio Vs Can be added to the Toolbox in Visual Studio
Good for static layout Vs Good for dynamic layout
What’s the difference between Response.Write() andResponse.Output.Write()?
Response.Output.Write() allows you to write formatted output
What is the use of ErrorProvider Control?
The ErrorProvider control is used to indicate invalid data on a data entry form. Using this control, you can attach error messages that display next to the control when the data is invalid, as seen in the following image. A red circle with an exclamation point blinks, and when the user mouses over the icon, the error message is displayed as a tooltip.
What is CLR?
Answer 1:
CLR(Common Language Runtime) is the main resource of .Net Framework. it is collection of services like garbage collector, exception handler, jit compilers etc. with the CLR cross language integration is possible.
Answer 2:
The .NET Framework provides a runtime environment which runs the code and provides services that make the development process easier. This runtime environment in .NET Framework is known as Common Language Runtime (CLR). The CLR sits at the very heart of managed code. Common Language Runtime is the generalized multi-language, reflective execution engine on which code originally written in various languages runs. At a higher level, CLR is simply an engine that takes in Intermediate Language (IL) instructions, translates them into machine instructions, and executes them. Although the common language runtime provides many standard runtime services, managed code is never interpreted. A feature called just-in-time (JIT) compiling enables all managed code to run in the native machine language of the system on which it is executing. The CLR shares much in common with a traditional operating system.
Quote:
Managed code is the term used for any code that is running on .NET Framework.
The CLR provides the infrastructure that enables managed code to execute as well provides variety of services during execution. When a method, for which IL has been generated, is called for the first time the CLR compiles the IL into native code that is specific to the processor the Environment it is running on (This process is known as Just in Time Compilation or JIT). If the same method is called next time, the existing JIT compiled code is reused. During execution managed code receives variety of services from the runtime environment.
Quote:
When compiling to managed code, the compiler translates your source code into Microsoft intermediate language (MSIL), which is a CPU-independent set of instructions that can be efficiently converted to native code. Intermediate Language is a binary assembly language that is compiled at runtime down to whatever machine language is appropriate for the host CPU. This runtime compilation is called Just-In-Time Compiling or JIT-compiling.
Advantages of Managed Execution Environments
In unmanaged environments the compiler and linker directly compile the source code in to native instructions that are targeted at a specific processor. The disadvantage of this process is that each time you want to run your executable on a different platform you will have to re-compile the code using a compiler and linker that will compile the code that is targeted at the specific hardware. This means that each time you want your application to run on a different platform, you will have to ship the compiled instructions again and again. As this leads to compiling and maintaining multiple versions of the same application, the companies try to create a more generalized compiled version in order to target most of the environments. This process is known as the Lowest Common Denominator approach. This leads to a more generalized program which is not optimized properly and does not take advantages of the underlying hardware infrastructure (processor, cache, etc). Because the CLR supplies one or more Just in Time Compiler for each computer architecture it supports, the same set of MSIL can be JIT-compiled and run on any supported architecture. This
CLR provides the following benefits for developers:
Vastly simplified development.
Seamless integration of code written in various languages.
Evidence-based security with code identity.
Assembly-based deployment that eliminates DLL Hell.
Side-by-side versioning of reusable components.
Code reuse through implementation inheritance.
Automatic object lifetime management.
Code access security.
Cross Language Integration.
Self describing objects.
The CLR automatically handles object layout and manages references to objects, releasing them when they are no longer being used. This automatic memory management resolves the two most common application errors, memory leaks and invalid memory references. This process is known as Garbage Collection. The CLR also manages thread execution, code execution, code safety verification, compilation, and other system services.
The CLR is designed for the software of the future, and it also supports software of today and yesterday. Interoperability between managed and unmanaged code provided by CLR helps developers continue to use necessary COM components and DLLs.
What is Delegate and what is it used for ?
Delegate is kinda like a pointer to a function in C++ or like an event handler in Java
You can use it to “multicast” which means running multiple functions in different instances of object already created.
This is useful when you want your objects to “register” to an event raised by another object.
The way it works is the object you are registered to listen to recieves the delegate of the function it is supposed to run in your object, the delegate is then run from it. (if you switch the word delegate for pointer, this would be much simpler)
How is meant by DLL ?
A DLL (Dynamic Link Library) is a file that can be loaded and executed by programs dynamically. Basically it’s an external code repository for programs. Since usually several different programs reuse the same DLL instead of having that code in their own file, this dramatically reduces required storage space. A synonym for a DLL would be library.
Which DLL translate XML to SQL in IIS?
Sqlisapi.dll
Can anyone tell me about Secure Socket Layer? How to make use of the technology?
Secure Sockets Layer (SSL) and Transport Layer Security (TLS), its successor, are cryptographic protocols which provide secure communications on the Internet. There are slight differences between SSL 3.0 and TLS 1.0, but the protocol remains substantially the same. The term “SSL” as used here applies to both protocols unless clarified by context.
Pros
====
ADO.NET is rich with plenty of features that are bound to impress even the most skeptical of programmers. If this weren’t the case, Microsoft wouldn’t even be able to get anyone to use the Beta. What we’ve done here is come up with a short list of some of the more outstanding benefits to using the ADO.NET architecture and the System.Data namespace.
* Performance – there is no doubt that ADO.NET is extremely fast. The actual figures vary depending on who performed the test and which benchmark was being used, but ADO.NET performs much, much faster at the same tasks than its predecessor, ADO. Some of the reasons why ADO.NET is faster than ADO are discussed in the ADO versus ADO.NET section later in this chapter.
* Optimized SQL Provider – in addition to performing well under general circumstances, ADO.NET includes a SQL Server Data Provider that is highly optimized for interaction with SQL Server. It uses SQL Server’s own TDS (Tabular Data Stream) format for exchanging information. Without question, your SQL Server 7 and above data access operations will run blazingly fast utilizing this optimized Data Provider.
* XML Support (and Reliance) – everything you do in ADO.NET at some point will boil down to the use of XML. In fact, many of the classes in ADO.NET, such as the DataSet, are so intertwined with XML that they simply cannot exist or function without utilizing the technology. You’ll see later when we compare and contrast the “old” and the “new” why the reliance on XML for internal storage provides many, many advantages, both to the framework and to the programmer utilizing the class library.
* Disconnected Operation Model – the core ADO.NET class, the DataSet, operates in an entirely disconnected fashion. This may be new to some programmers, but it is a remarkably efficient and scalable architecture. Because the disconnected model allows for the DataSet class to be unaware of the origin of its data, an unlimited number of supported data sources can be plugged into code without any hassle in the future.
* Rich Object Model – the entire ADO.NET architecture is built on a hierarchy of class inheritance and interface implementation. Once you start looking for things you need within this namespace, you’ll find that the logical inheritance of features and base class support makes the entire system extremely easy to use, and very customizable to suit your own needs. It is just another example of how everything in the .NET framework is pushing toward a trend of strong application design and strong OOP implementations.
Cons
====
Hard as it may be to believe, there are a couple of drawbacks or disadvantages to using the ADO.NET architecture. I’m sure others can find many more faults than we list here, but we decided to stick with a short list of some of the more obvious and important shortcomings of the technology.
* Managed-Only Access – for a few obvious reasons, and some far more technical, you cannot utilize the ADO.NET architecture from anything but managed code. This means that there is no COM interoperability allowed for ADO.NET. Therefore, in order to take advantage of the advanced SQL Server Data Provider and any other feature like DataSets, XML internal data storage, etc, your code must be running under the CLR.
* Only Three Managed Data Providers (so far) – unfortunately, if you need to access any data that requires a driver that cannot be used through either an OLEDB provider or the SQL Server Data Provider, then you may be out of luck. However, the good news is that the OLEDB provider for ODBC is available for download from Microsoft. At that point the down-side becomes one of performance, in which you are invoking multiple layers of abstraction as well as crossing the COM InterOp gap, incurring some initial overhead as well.
* Learning Curve – despite the misleading name, ADO.NET is not simply a new version of ADO, nor should it even be considered a direct successor. ADO.NET should be thought of more as the data access class library for use with the .NET framework. The difficulty in learning to use ADO.NET to its fullest is that a lot of it does seem familiar. It is this that causes some common pitfalls. Programmers need to learn that even though some syntax may appear the same, there is actually a considerable amount of difference in the internal workings of many classes. For example (this will be discussed in far more detail later), an ADO.NET DataSet is nothing at all like a disconnected ADO RecordSet. Some may consider a learning curve a drawback, but I consider learning curves more like scheduling issues. There’s a learning curve in learning anything new; it’s just up to you to schedule that curve into your time so that you can learn the new technology at a pace that fits your schedule.
Why The JavaScript Validation Not Run on the Asp.Net Button But Run SuccessFully On The HTML Button
The Asp.Net Button Is post backed on the server & not yet Submit & when It goes to the server its states is lost So if we r using javascript in our application so we always use the Input Button in the asp Button
what is the difference between user control an custom control? advantages/disadvantages?
Web user controls Vs Web custom controls
Easier to create Vs Harder to create
Limited support for consumers who use a visual design tool Vs Full visual design tool support for consumers
A separate copy of the control is required in each application Vs Only a single copy of the control is required, in the global assembly cache
Cannot be added to the Toolbox in Visual Studio Vs Can be added to the Toolbox in Visual Studio
Good for static layout Vs Good for dynamic layout
What’s the difference between Response.Write() andResponse.Output.Write()?
Response.Output.Write() allows you to write formatted output
What is the use of ErrorProvider Control?
The ErrorProvider control is used to indicate invalid data on a data entry form. Using this control, you can attach error messages that display next to the control when the data is invalid, as seen in the following image. A red circle with an exclamation point blinks, and when the user mouses over the icon, the error message is displayed as a tooltip.
What is CLR?
Answer 1:
CLR(Common Language Runtime) is the main resource of .Net Framework. it is collection of services like garbage collector, exception handler, jit compilers etc. with the CLR cross language integration is possible.
Answer 2:
The .NET Framework provides a runtime environment which runs the code and provides services that make the development process easier. This runtime environment in .NET Framework is known as Common Language Runtime (CLR). The CLR sits at the very heart of managed code. Common Language Runtime is the generalized multi-language, reflective execution engine on which code originally written in various languages runs. At a higher level, CLR is simply an engine that takes in Intermediate Language (IL) instructions, translates them into machine instructions, and executes them. Although the common language runtime provides many standard runtime services, managed code is never interpreted. A feature called just-in-time (JIT) compiling enables all managed code to run in the native machine language of the system on which it is executing. The CLR shares much in common with a traditional operating system.
Quote:
Managed code is the term used for any code that is running on .NET Framework.
The CLR provides the infrastructure that enables managed code to execute as well provides variety of services during execution. When a method, for which IL has been generated, is called for the first time the CLR compiles the IL into native code that is specific to the processor the Environment it is running on (This process is known as Just in Time Compilation or JIT). If the same method is called next time, the existing JIT compiled code is reused. During execution managed code receives variety of services from the runtime environment.
Quote:
When compiling to managed code, the compiler translates your source code into Microsoft intermediate language (MSIL), which is a CPU-independent set of instructions that can be efficiently converted to native code. Intermediate Language is a binary assembly language that is compiled at runtime down to whatever machine language is appropriate for the host CPU. This runtime compilation is called Just-In-Time Compiling or JIT-compiling.
Advantages of Managed Execution Environments
In unmanaged environments the compiler and linker directly compile the source code in to native instructions that are targeted at a specific processor. The disadvantage of this process is that each time you want to run your executable on a different platform you will have to re-compile the code using a compiler and linker that will compile the code that is targeted at the specific hardware. This means that each time you want your application to run on a different platform, you will have to ship the compiled instructions again and again. As this leads to compiling and maintaining multiple versions of the same application, the companies try to create a more generalized compiled version in order to target most of the environments. This process is known as the Lowest Common Denominator approach. This leads to a more generalized program which is not optimized properly and does not take advantages of the underlying hardware infrastructure (processor, cache, etc). Because the CLR supplies one or more Just in Time Compiler for each computer architecture it supports, the same set of MSIL can be JIT-compiled and run on any supported architecture. This
CLR provides the following benefits for developers:
Vastly simplified development.
Seamless integration of code written in various languages.
Evidence-based security with code identity.
Assembly-based deployment that eliminates DLL Hell.
Side-by-side versioning of reusable components.
Code reuse through implementation inheritance.
Automatic object lifetime management.
Code access security.
Cross Language Integration.
Self describing objects.
The CLR automatically handles object layout and manages references to objects, releasing them when they are no longer being used. This automatic memory management resolves the two most common application errors, memory leaks and invalid memory references. This process is known as Garbage Collection. The CLR also manages thread execution, code execution, code safety verification, compilation, and other system services.
The CLR is designed for the software of the future, and it also supports software of today and yesterday. Interoperability between managed and unmanaged code provided by CLR helps developers continue to use necessary COM components and DLLs.
What is Delegate and what is it used for ?
Delegate is kinda like a pointer to a function in C++ or like an event handler in Java
You can use it to “multicast” which means running multiple functions in different instances of object already created.
This is useful when you want your objects to “register” to an event raised by another object.
The way it works is the object you are registered to listen to recieves the delegate of the function it is supposed to run in your object, the delegate is then run from it. (if you switch the word delegate for pointer, this would be much simpler)
How is meant by DLL ?
A DLL (Dynamic Link Library) is a file that can be loaded and executed by programs dynamically. Basically it’s an external code repository for programs. Since usually several different programs reuse the same DLL instead of having that code in their own file, this dramatically reduces required storage space. A synonym for a DLL would be library.
Which DLL translate XML to SQL in IIS?
Sqlisapi.dll
Can anyone tell me about Secure Socket Layer? How to make use of the technology?
Secure Sockets Layer (SSL) and Transport Layer Security (TLS), its successor, are cryptographic protocols which provide secure communications on the Internet. There are slight differences between SSL 3.0 and TLS 1.0, but the protocol remains substantially the same. The term “SSL” as used here applies to both protocols unless clarified by context.
Microsoft .Net Interview Questions and Answers
What is the base class of .NET?
Base class provides a base set of methods that all derived classes can use
Explain assemblies.
Answer 1:
Assemblies are similar to dll files. Both has the reusable pieces of code in the form of classes/ functions. Dll needs to be registered but assemblies have its own metadata.
Answer 2:
Assembly is a single deployable unit that contains information about the implementation of classes, structures and interfaces. it also stores the information about itself called metadata and includes name and verison of the assembly, security information, information about the dependencies and the list of files that constitute the assembly.
Assembly also contains namespaces. In the .Net Framework, applications are deployed in the form of assemblies.
Answer 3:
An assembly is a single deployable unit that contains all the information about the implementation of :
- classes
- structures and
- interfaces
An assembly stores all the information about itself. This information is called METADATA and include the name and the verison number of the assembly, security information, information about the dependencies and a lost of files that constitute the assembly.
All the application developed using the .NET framework are made up of assemblies.
Namespaces are also stored in assemblies
Answer 4:
In the Microsoft .NET framework an assembly is a partially compiled code library for use in deployment, versioning and security. In the Microsoft Windows implementation of .NET, an assembly is a PE (portable executable) file. There are two types, process assemblies (EXE) and library assemblies (DLL). A process assembly represents a process which will use classes defined in library assemblies. In version 1.1 of the CLR classes can only be exported from library assemblies; in version 2.0 this restriction is relaxed. The compiler will have a switch to determine if the assembly is a process or library and will set a flag in the PE file. .NET does not use the extension to determine if the file is a process or library. This means that a library may have either .dll or .exe as its extension.
The code in an assembly is partially compiled into CIL, which is then fully compiled into machine language at runtime by the CLR.
An assembly can consist of one or more files. Code files are called modules. An assembly can contain more than one code module and since it is possible to use different languages to create code modules this means that it is technically possible to use several different languages to create an assembly. In practice this rarely happens, principally because Visual Studio only allows developers to create assemblies that consist of a single code module.
Name some of the languages .NET support?
Some of the languages that are supported by .NET
1. Visual Basic.NET
2. Visual C#
3. Visual C++
ADO.NET features? Benefits? Drawbacks?
Answer 1:
1. Data will be retrieved through Datasets
2. Scalability
Answer 2:
1. Disconnected Data Architecture
2. Data cached in Datasets
3. Data transfer in XML format
4. Interaction with the database is done through data commands
How many types of exception handlers are there in .NET?
Answer 1:
From
MSDN>gt; “How the Runtime Manages Exceptions”
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconexceptionsoverview.asp
The exception information table represents four types of exception handlers for protected blocks:
A finally handler that executes whenever the block exits, whether that occurs by normal control flow or by an unhandled exception.
A fault handler that must execute if an exception occurs, but does not execute on completion of normal control flow.
A type-filtered handler that handles any exception of a specified class or any of its derived classes.
A user-filtered handler that runs user-specified code to determine whether the exception should be handled by the associated handler or should be passed to the next protected block.
Answer 2:
1. Unstructured Exception Handling
2. Structured Exception Handling
Difference between Panel and GroupBox classes?
Answer 1:
Panel and Group box both can used as container for other controls like radio buttons and check box.
the difference in panel and group box are Panel
1) In case of panel captions cannot be displayed
2) Can have scroll bars.
Group box
1) Captions can be displayed.
2) Cannot have a scroll bar
Answer 2:
Panel is scrollable. In panel you can’t set caption like Group box.
What is the base class of Button control?
Listing from visual studio .net > Button Class
System.Object
System.MarshalByRefObject
System.ComponentModel.Component
System.Windows.Forms.Control
System.Windows.Forms.ButtonBase
System.Windows.Forms.Button
What is Response object? How is it related to ASP’s Response object?
Response object allows the server to communicate with the client(browser). It is useful for displaying information to the user (or) redirecting the client.
Eg: Response.Write(”Hello World”)
hat is IIS? Have you used it?
IIS - Internet Information Server
IIS is used to access the ASP.Net web applications
Yes, I used in ASP.NET web applications.
Main differences between ASP and ASP.NET.
Answer 1:
1. ASP: Code is Interpreted
ASP.NET: Code is Compiled
2. ASP: Business Logic and Presentation Logic are in a single file
ASP.NET: Business Logic and Presentation Logic are in separate files (.cs or .vb) and (.aspx) respectively.
3. ASP: No Web Server Controls
ASP.NET: Web Server Controls supported by strong .NET Framework
4. ASP: No RAD in Classic ASP
ASP.NET: Supports RAD
Answer 2:
1.Asp is interpreted
Asp.net is compiled which is faster than asp.
2 Asp.net maintains its own CLR and is managed as it runs by CLR
Where as asp is unmanaged
3 We can mainatin sessions in state server and sql server which is Outproc,
where in asp sessions will be last if we restart webserver or make changes.
4 In asp.net we can configure each application using web.config file which is availble in application itself and we have machine.config wherer we can configure all applications.
In asp we cannot configure single aplication
5 Asp.net we have autopostback event which is not in asp
6 In asp.net we have global.asax where can hadle some global things which is not in asp.
7 We have well built GUI to work in asp.net
8 We have ado.net and as well as disconnected architecture in asp.net
9 We have Xcopy deployment in asp.net
10. We can work with any language as code behind technique in asp.net that supports .net frame work
Answer 3:
a) asp.net is compiled but ASP is a interpretor or script only.
b) asp.net is supported more control then the asp.
c) asp.net is more supported even control then the asp.
d) In asp.net if update any component then no need to shutdown the computer but in asp if loaded any component then need tobe shutdown the computer.
d) So lastly an asp.net is faster then asp .
Base class provides a base set of methods that all derived classes can use
Explain assemblies.
Answer 1:
Assemblies are similar to dll files. Both has the reusable pieces of code in the form of classes/ functions. Dll needs to be registered but assemblies have its own metadata.
Answer 2:
Assembly is a single deployable unit that contains information about the implementation of classes, structures and interfaces. it also stores the information about itself called metadata and includes name and verison of the assembly, security information, information about the dependencies and the list of files that constitute the assembly.
Assembly also contains namespaces. In the .Net Framework, applications are deployed in the form of assemblies.
Answer 3:
An assembly is a single deployable unit that contains all the information about the implementation of :
- classes
- structures and
- interfaces
An assembly stores all the information about itself. This information is called METADATA and include the name and the verison number of the assembly, security information, information about the dependencies and a lost of files that constitute the assembly.
All the application developed using the .NET framework are made up of assemblies.
Namespaces are also stored in assemblies
Answer 4:
In the Microsoft .NET framework an assembly is a partially compiled code library for use in deployment, versioning and security. In the Microsoft Windows implementation of .NET, an assembly is a PE (portable executable) file. There are two types, process assemblies (EXE) and library assemblies (DLL). A process assembly represents a process which will use classes defined in library assemblies. In version 1.1 of the CLR classes can only be exported from library assemblies; in version 2.0 this restriction is relaxed. The compiler will have a switch to determine if the assembly is a process or library and will set a flag in the PE file. .NET does not use the extension to determine if the file is a process or library. This means that a library may have either .dll or .exe as its extension.
The code in an assembly is partially compiled into CIL, which is then fully compiled into machine language at runtime by the CLR.
An assembly can consist of one or more files. Code files are called modules. An assembly can contain more than one code module and since it is possible to use different languages to create code modules this means that it is technically possible to use several different languages to create an assembly. In practice this rarely happens, principally because Visual Studio only allows developers to create assemblies that consist of a single code module.
Name some of the languages .NET support?
Some of the languages that are supported by .NET
1. Visual Basic.NET
2. Visual C#
3. Visual C++
ADO.NET features? Benefits? Drawbacks?
Answer 1:
1. Data will be retrieved through Datasets
2. Scalability
Answer 2:
1. Disconnected Data Architecture
2. Data cached in Datasets
3. Data transfer in XML format
4. Interaction with the database is done through data commands
How many types of exception handlers are there in .NET?
Answer 1:
From
MSDN>gt; “How the Runtime Manages Exceptions”
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconexceptionsoverview.asp
The exception information table represents four types of exception handlers for protected blocks:
A finally handler that executes whenever the block exits, whether that occurs by normal control flow or by an unhandled exception.
A fault handler that must execute if an exception occurs, but does not execute on completion of normal control flow.
A type-filtered handler that handles any exception of a specified class or any of its derived classes.
A user-filtered handler that runs user-specified code to determine whether the exception should be handled by the associated handler or should be passed to the next protected block.
Answer 2:
1. Unstructured Exception Handling
2. Structured Exception Handling
Difference between Panel and GroupBox classes?
Answer 1:
Panel and Group box both can used as container for other controls like radio buttons and check box.
the difference in panel and group box are Panel
1) In case of panel captions cannot be displayed
2) Can have scroll bars.
Group box
1) Captions can be displayed.
2) Cannot have a scroll bar
Answer 2:
Panel is scrollable. In panel you can’t set caption like Group box.
What is the base class of Button control?
Listing from visual studio .net > Button Class
System.Object
System.MarshalByRefObject
System.ComponentModel.Component
System.Windows.Forms.Control
System.Windows.Forms.ButtonBase
System.Windows.Forms.Button
What is Response object? How is it related to ASP’s Response object?
Response object allows the server to communicate with the client(browser). It is useful for displaying information to the user (or) redirecting the client.
Eg: Response.Write(”Hello World”)
hat is IIS? Have you used it?
IIS - Internet Information Server
IIS is used to access the ASP.Net web applications
Yes, I used in ASP.NET web applications.
Main differences between ASP and ASP.NET.
Answer 1:
1. ASP: Code is Interpreted
ASP.NET: Code is Compiled
2. ASP: Business Logic and Presentation Logic are in a single file
ASP.NET: Business Logic and Presentation Logic are in separate files (.cs or .vb) and (.aspx) respectively.
3. ASP: No Web Server Controls
ASP.NET: Web Server Controls supported by strong .NET Framework
4. ASP: No RAD in Classic ASP
ASP.NET: Supports RAD
Answer 2:
1.Asp is interpreted
Asp.net is compiled which is faster than asp.
2 Asp.net maintains its own CLR and is managed as it runs by CLR
Where as asp is unmanaged
3 We can mainatin sessions in state server and sql server which is Outproc,
where in asp sessions will be last if we restart webserver or make changes.
4 In asp.net we can configure each application using web.config file which is availble in application itself and we have machine.config wherer we can configure all applications.
In asp we cannot configure single aplication
5 Asp.net we have autopostback event which is not in asp
6 In asp.net we have global.asax where can hadle some global things which is not in asp.
7 We have well built GUI to work in asp.net
8 We have ado.net and as well as disconnected architecture in asp.net
9 We have Xcopy deployment in asp.net
10. We can work with any language as code behind technique in asp.net that supports .net frame work
Answer 3:
a) asp.net is compiled but ASP is a interpretor or script only.
b) asp.net is supported more control then the asp.
c) asp.net is more supported even control then the asp.
d) In asp.net if update any component then no need to shutdown the computer but in asp if loaded any component then need tobe shutdown the computer.
d) So lastly an asp.net is faster then asp .
.Net Interview Questions and Answers 10
What is .NET?
.NET is essentially a framework for software development. It is similar in nature to any other software development framework (J2EE etc) in that it provides a set of runtime containers/capabilities, and a rich set of pre-built functionality in the form of class libraries and APIs
The .NET Framework is an environment for building, deploying, and running Web Services and other applications. It consists of three main parts: the Common Language Runtime, the Framework classes, and ASP.NET.
How many languages .NET is supporting now?
When .NET was introduced it came with several languages. VB.NET, C#, COBOL and Perl, etc. The site DotNetLanguages.Net says 44 languages are supported.
How is .NET able to support multiple languages?
A language should comply with the Common Language Runtime standard to become a .NET language. In .NET, code is compiled to Microsoft Intermediate Language (MSIL for short). This is called as Managed Code. This Managed code is run in .NET environment. So after compilation to this IL the language is not a barrier. A code can call or use a function written in another language.
How ASP .NET different from ASP?
Scripting is separated from the HTML, Code is compiled as a DLL, these DLLs can be executed on the server.
What is smart navigation?
The cursor position is maintained when the page gets refreshed due to the server side validation and the page gets refreshed.
What is view state?
The web is stateless. But in ASP.NET, the state of a page is maintained in the in the page itself automatically. How? The values are encrypted and saved in hidden controls. this is done automatically by the ASP.NET. This can be switched off / on for a single control
How do you validate the controls in an ASP .NET page?
Using special validation controls that are meant for this. We have Range Validator, Email Validator.
Can the validation be done in the server side? Or this can be done only in the Client side?
Security Tip
Use Firefox instead of Internet Explorer and PREVENT Spyware !
Firefox is free and is considered the best free, safe web browser available today
Browse the web faster. Get Firefox with Google Toolbar
Client side is done by default. Server side validation is also possible. We can switch off the client side and server side can be done.
How to manage pagination in a page?
Using pagination option in DataGrid control. We have to set the number of records for a page, then it takes care of pagination by itself.
What is ADO .NET and what is difference between ADO and ADO.NET?
ADO.NET is stateless mechanism. I can treat the ADO.Net as a separate in-memory database where in I can use relationships between the tables and select insert and updates to the database. I can update the actual database as a batch.
Observations between VB.NET and VC#.NET?
Choosing a programming language depends on your language experience and the scope of the application you are building. While small applications are often created using only one language, it is not uncommon to develop large applications using multiple languages.
For example, if you are extending an application with existing XML Web services, you might use a scripting language with little or no programming effort. For client-server applications, you would probably choose the single language you are most comfortable with for the entire application. For new enterprise applications, where large teams of developers create components and services for deployment across multiple remote sites, the best choice might be to use several languages depending on developer skills and long-term maintenance expectations.
The .NET Platform programming languages - including Visual Basic .NET, Visual C#, and Visual C++ with managed extensions, and many other programming languages from various vendors - use .NET Framework services and features through a common set of unified classes. The .NET unified classes provide a consistent method of accessing the platform's functionality. If you learn to use the class library, you will find that all tasks follow the same uniform architecture. You no longer need to learn and master different API architectures to write your applications.
In most situations, you can effectively use all of the Microsoft programming languages. Nevertheless, each programming language has its relative strengths and you will want to understand the features unique to each language. The following sections will help you choose the right programming language for your application.
Visual Basic .NET
Visual Basic .NET is the next generation of the Visual Basic language from Microsoft. With Visual Basic you can build .NET applications, including Web services and ASP.NET Web applications, quickly and easily. Applications made with Visual Basic are built on the services of the common language runtime and take advantage of the .NET Framework.
Visual Basic has many new and improved features such as inheritance, interfaces, and overloading that make it a powerful object-oriented programming language. Other new language features include free threading and structured exception handling. Visual Basic fully integrates the .NET Framework and the common language runtime, which together provide language interoperability, garbage collection, enhanced security, and improved versioning support. A Visual Basic support single inheritance and creates Microsoft intermediate language (MSIL) as input to native code compilers.
Visual Basic is comparatively easy to learn and use, and Visual Basic has become the programming language of choice for hundreds of thousands of developers over the past decade. An understanding of Visual Basic can be leveraged in a variety of ways, such as writing macros in Visual Studio and providing programmability in applications such as Microsoft Excel, Access, and Word.
Visual Basic provides prototypes of some common project types, including:
• Windows Application.
• Class Library.
• Windows Control Library.
• ASP.NET Web Application.
• ASP.NET Web Service.
• Web Control Library.
• Console Application.
• Windows Service.
• Windows Service.
Visual C# .NET
Visual C# (pronounced C sharp) is designed to be a fast and easy way to create .NET applications, including Web services and ASP.NET Web applications. Applications written in Visual C# are built on the services of the common language runtime and take full advantage of the .NET Framework.
C# is a simple, elegant, type-safe, object-oriented language recently developed by Microsoft for building a wide range of applications. Anyone familiar with C and similar languages will find few problems in adapting to C#. C# is designed to bring rapid development to the C++ programmer without sacrificing the power and control that are a hallmark of C and C++. Because of this heritage, C# has a high degree of fidelity with C and C++, and developers familiar with these languages can quickly become productive in C#. C# provides intrinsic code trust mechanisms for a high level of security, garbage collection, and type safety. C# supports single inheritance and creates Microsoft intermediate language (MSIL) as input to native code compilers.
C# is fully integrated with the .NET Framework and the common language runtime, which together provide language interoperability, garbage collection, enhanced security, and improved versioning support. C# simplifies and modernizes some of the more complex aspects of C and C++, notably namespaces, classes, enumerations, overloading, and structured exception handling. C# also eliminates C and C++ features such as macros, multiple inheritance, and virtual base classes. For current C++ developers, C# provides a powerful, high-productivity language alternative.
Visual C# provides prototypes of some common project types, including:
• Windows Application.
• Class Library.
• Windows Control Library.
• ASP.NET Web Application.
• ASP.NET Web Service.
• Web Control Library.
• Console Application.
• Windows Service.
.NET is essentially a framework for software development. It is similar in nature to any other software development framework (J2EE etc) in that it provides a set of runtime containers/capabilities, and a rich set of pre-built functionality in the form of class libraries and APIs
The .NET Framework is an environment for building, deploying, and running Web Services and other applications. It consists of three main parts: the Common Language Runtime, the Framework classes, and ASP.NET.
How many languages .NET is supporting now?
When .NET was introduced it came with several languages. VB.NET, C#, COBOL and Perl, etc. The site DotNetLanguages.Net says 44 languages are supported.
How is .NET able to support multiple languages?
A language should comply with the Common Language Runtime standard to become a .NET language. In .NET, code is compiled to Microsoft Intermediate Language (MSIL for short). This is called as Managed Code. This Managed code is run in .NET environment. So after compilation to this IL the language is not a barrier. A code can call or use a function written in another language.
How ASP .NET different from ASP?
Scripting is separated from the HTML, Code is compiled as a DLL, these DLLs can be executed on the server.
What is smart navigation?
The cursor position is maintained when the page gets refreshed due to the server side validation and the page gets refreshed.
What is view state?
The web is stateless. But in ASP.NET, the state of a page is maintained in the in the page itself automatically. How? The values are encrypted and saved in hidden controls. this is done automatically by the ASP.NET. This can be switched off / on for a single control
How do you validate the controls in an ASP .NET page?
Using special validation controls that are meant for this. We have Range Validator, Email Validator.
Can the validation be done in the server side? Or this can be done only in the Client side?
Security Tip
Use Firefox instead of Internet Explorer and PREVENT Spyware !
Firefox is free and is considered the best free, safe web browser available today
Browse the web faster. Get Firefox with Google Toolbar
Client side is done by default. Server side validation is also possible. We can switch off the client side and server side can be done.
How to manage pagination in a page?
Using pagination option in DataGrid control. We have to set the number of records for a page, then it takes care of pagination by itself.
What is ADO .NET and what is difference between ADO and ADO.NET?
ADO.NET is stateless mechanism. I can treat the ADO.Net as a separate in-memory database where in I can use relationships between the tables and select insert and updates to the database. I can update the actual database as a batch.
Observations between VB.NET and VC#.NET?
Choosing a programming language depends on your language experience and the scope of the application you are building. While small applications are often created using only one language, it is not uncommon to develop large applications using multiple languages.
For example, if you are extending an application with existing XML Web services, you might use a scripting language with little or no programming effort. For client-server applications, you would probably choose the single language you are most comfortable with for the entire application. For new enterprise applications, where large teams of developers create components and services for deployment across multiple remote sites, the best choice might be to use several languages depending on developer skills and long-term maintenance expectations.
The .NET Platform programming languages - including Visual Basic .NET, Visual C#, and Visual C++ with managed extensions, and many other programming languages from various vendors - use .NET Framework services and features through a common set of unified classes. The .NET unified classes provide a consistent method of accessing the platform's functionality. If you learn to use the class library, you will find that all tasks follow the same uniform architecture. You no longer need to learn and master different API architectures to write your applications.
In most situations, you can effectively use all of the Microsoft programming languages. Nevertheless, each programming language has its relative strengths and you will want to understand the features unique to each language. The following sections will help you choose the right programming language for your application.
Visual Basic .NET
Visual Basic .NET is the next generation of the Visual Basic language from Microsoft. With Visual Basic you can build .NET applications, including Web services and ASP.NET Web applications, quickly and easily. Applications made with Visual Basic are built on the services of the common language runtime and take advantage of the .NET Framework.
Visual Basic has many new and improved features such as inheritance, interfaces, and overloading that make it a powerful object-oriented programming language. Other new language features include free threading and structured exception handling. Visual Basic fully integrates the .NET Framework and the common language runtime, which together provide language interoperability, garbage collection, enhanced security, and improved versioning support. A Visual Basic support single inheritance and creates Microsoft intermediate language (MSIL) as input to native code compilers.
Visual Basic is comparatively easy to learn and use, and Visual Basic has become the programming language of choice for hundreds of thousands of developers over the past decade. An understanding of Visual Basic can be leveraged in a variety of ways, such as writing macros in Visual Studio and providing programmability in applications such as Microsoft Excel, Access, and Word.
Visual Basic provides prototypes of some common project types, including:
• Windows Application.
• Class Library.
• Windows Control Library.
• ASP.NET Web Application.
• ASP.NET Web Service.
• Web Control Library.
• Console Application.
• Windows Service.
• Windows Service.
Visual C# .NET
Visual C# (pronounced C sharp) is designed to be a fast and easy way to create .NET applications, including Web services and ASP.NET Web applications. Applications written in Visual C# are built on the services of the common language runtime and take full advantage of the .NET Framework.
C# is a simple, elegant, type-safe, object-oriented language recently developed by Microsoft for building a wide range of applications. Anyone familiar with C and similar languages will find few problems in adapting to C#. C# is designed to bring rapid development to the C++ programmer without sacrificing the power and control that are a hallmark of C and C++. Because of this heritage, C# has a high degree of fidelity with C and C++, and developers familiar with these languages can quickly become productive in C#. C# provides intrinsic code trust mechanisms for a high level of security, garbage collection, and type safety. C# supports single inheritance and creates Microsoft intermediate language (MSIL) as input to native code compilers.
C# is fully integrated with the .NET Framework and the common language runtime, which together provide language interoperability, garbage collection, enhanced security, and improved versioning support. C# simplifies and modernizes some of the more complex aspects of C and C++, notably namespaces, classes, enumerations, overloading, and structured exception handling. C# also eliminates C and C++ features such as macros, multiple inheritance, and virtual base classes. For current C++ developers, C# provides a powerful, high-productivity language alternative.
Visual C# provides prototypes of some common project types, including:
• Windows Application.
• Class Library.
• Windows Control Library.
• ASP.NET Web Application.
• ASP.NET Web Service.
• Web Control Library.
• Console Application.
• Windows Service.
.Net Interview Questions and Answers 8
Advantages of migrating to VB.NET ?
Visual Basic .NET has many new and improved language features — such as inheritance, interfaces, and overloading that make it a powerful object-oriented programming language. As a Visual Basic developer, you can now create multithreaded, scalable applications using explicit multithreading. Other new language features in Visual Basic .NET include structured exception handling, custom attributes, and common language specification (CLS) compliance.
The CLS is a set of rules that standardizes such things as data types and how objects are exposed and interoperate. Visual Basic .NET adds several features that take advantage of the CLS. Any CLS-compliant language can use the classes, objects, and components you create in Visual Basic .NET. And you, as a Visual Basic user, can access classes, components, and objects from other CLS-compliant programming languages without worrying about language-specific differences such as data types.
CLS features used by Visual Basic .NET programs include assemblies, namespaces, and attributes.
These are the new features to be stated briefly:
Inheritance
Visual Basic .NET supports inheritance by allowing you to define classes that serve as the basis for derived classes. Derived classes inherit and can extend the properties and methods of the base class. They can also override inherited methods with new implementations. All classes created with Visual Basic .NET are inheritable by default. Because the forms you design are really classes, you can use inheritance to define new forms based on existing ones.
Exception Handling
Visual Basic .NET supports structured exception handling, using an enhanced version of the Try...Catch...Finally syntax supported by other languages such as C++.
Structured exception handling combines a modern control structure (similar to Select Case or While) with exceptions, protected blocks of code, and filters. Structured exception handling makes it easy to create and maintain programs with robust, comprehensive error handlers.
Overloading
Overloading is the ability to define properties, methods, or procedures that have the same name but use different data types. Overloaded procedures allow you to provide as many implementations as necessary to handle different kinds of data, while giving the appearance of a single, versatile procedure. Overriding Properties and Methods The Overrides keyword allows derived objects to override characteristics inherited from parent objects. Overridden members have the same arguments as the members inherited from the base class, but different implementations. A member's new implementation can call the original implementation in the parent class by preceding the member name with MyBase.
Constructors and Destructors
Constructors are procedures that control initialization of new instances of a class. Conversely, destructors are methods that free system resources when a class leaves scope or is set to Nothing. Visual Basic .NET supports constructors and destructors using the Sub New and Sub Finalize procedures.
Data Types
Visual Basic .NET introduces three new data types. The Char data type is an unsigned 16-bit quantity used to store Unicode characters. It is equivalent to the .NET Framework System. Char data type. The Short data type, a signed 16-bit integer, was named Integer in earlier versions of Visual Basic. The Decimal data type is a 96-bit signed integer scaled by a variable power of 10. In earlier versions of Visual Basic, it was available only within a Variant.
Interfaces
Interfaces describe the properties and methods of classes, but unlike classes, do not provide implementations. The Interface statement allows you to declare interfaces, while the Implements statement lets you write code that puts the items described in the interface into practice.
Delegates
Delegates objects that can call the methods of objects on your behalf are sometimes described as type-safe, object-oriented function pointers. You can use delegates to let procedures specify an event handler method that runs when an event occurs. You can also use delegates with multithreaded applications. For details, see Delegates and the AddressOf Operator.
Shared Members
Shared members are properties, procedures, and fields that are shared by all instances of a class. Shared data members are useful when multiple objects need to use information that is common to all. Shared class methods can be used without first creating an object from a class.
References
References allow you to use objects defined in other assemblies. In Visual Basic .NET, references point to assemblies instead of type libraries. For details, see References and the Imports Statement. Namespaces prevent naming conflicts by organizing classes, interfaces, and methods into hierarchies.
Assemblies
Assemblies replace and extend the capabilities of type libraries by, describing all the required files for a particular component or application. An assembly can contain one or more namespaces.
Attributes
Attributes enable you to provide additional information about program elements. For example, you can use an attribute to specify which methods in a class should be exposed when the class is used as a XML Web service.
Multithreading
Visual Basic .NET allows you to write applications that can perform multiple tasks independently. A task that has the potential of holding up other tasks can execute on a separate thread, a process known as multithreading. By causing complicated tasks to run on threads that are separate from your user interface, multithreading makes your applications more responsive to user input.
Using ActiveX Control in .Net
ActiveX control is a special type of COM component that supports a User Interface. Using ActiveX Control in your .Net Project is even easier than using COM component. They are bundled usually in .ocx files. Again a proxy assembly is made by .Net utility AxImp.exe (which we will see shortly) which your application (or client) uses as if it is a .Net control or assembly.
Making Proxy Assembly For ActiveX Control: First, a proxy assembly is made using AxImp.exe (acronym for ActiveX Import) by writing following command on Command Prompt:
C:> AxImp C:MyProjectsMyControl.ocx
This command will make two dlls, e.g., in case of above command
MyControl.dll
AxMyControl.dll
The first file MyControl.dll is a .Net assembly proxy, which allows you to reference the ActiveX as if it were non-graphical object.
The second file AxMyControl.dll is the Windows Control, which allows u to use the graphical aspects of activex control and use it in the Windows Form Project.
Adding Reference of ActiveX Proxy Assembly in your Project Settings: To add a reference of ActiveX Proxy Assembly in our Project, do this:
o Select Project A Add Reference (Select Add Reference from Project Menu).
o This will show you a dialog box, select .Net tab from the top of window.
o Click Browse button on the top right of window.
o Select the dll file for your ActiveX Proxy Assembly (which is MyControl.dll) and click OK o Your selected component is now shown in the ‘Selected Component’ List Box. Click OK again Some More On Using COM or ActiveX in .Net
.Net only provides wrapper class or proxy assembly (Runtime Callable Wrapper or RCW) for COM or activeX control. In the background, it is actually delegating the tasks to the original COM, so it does not convert your COM/activeX but just imports them.
A good thing about .Net is that when it imports a component, it also imports the components that are publically referenced by that component. So, if your component, say MyDataAcsess.dll references ADODB.dll then .Net will automatically import that COM component too!
The Visual Studio.NET does surprise you in a great deal when u see that it is applying its intellisense (showing methods, classes, interfaces, properties when placing dot) even on your imported COM components!!!! Isn’t it a magic or what?
When accessing thru RCW, .Net client has no knowledge that it is using COM component, it is presented just as another C# assembly.
U can also import COM component thru command prompt (for reference see Professional C# by Wrox)
U can also use your .Net components in COM, i.e., export your .net components (for reference see Professional C# by Wrox)
What is Machine.config?
Machine configuration file: The machine.config file contains settings that apply to the entire computer. This file is located in the %runtime install path%Config directory. There is only one machine.config file on a computer. The Machine.Config file found in the "CONFIG" subfolder of your .NET Framework install directory (c:WINNTMicrosoft.NETFramework{Version Number} CONFIG on Windows 2000 installations). The machine.config, which can be found in the directory $WINDIR$Microsoft.NETFrameworkv1.0.3705CONFIG, is an XML-formatted configuration file that specifies configuration options for the machine. This file contains, among many other XML elements, a browser Caps element. Inside this element are a number of other elements that specify parse rules for the various User-Agents, and what properties each of these parsing supports.
For example, to determine what platform is used, a filter element is used that specifies how to set the platform property based on what platform name is found in the User-Agent string. Specifically, the machine.config file contains:
platform=Win95
platform=Win98
platform=WinNT
...
That is, if in the User-Agent string the string "Windows 95" or "Win95" is found, the platform property is set to Win95. There are a number of filter elements in the browserCaps element in the machine.config file that define the various properties for various User-Agent strings.
Hence, when using the Request.Browser property to determine a user's browser features, the user's agent string is matched up to particular properties in the machine.config file. The ability for being able to detect a user's browser's capabilities, then, is based upon the honesty in the browser's sent User-Agent string. For example, Opera can be easily configured to send a User-Agent string that makes it appear as if it's IE 5.5. In this case from the Web server's perspective (and, hence, from your ASP.NET Web page's perspective), the user is visiting using IE 5.5, even though, in actuality, he is using Opera.
What is Web.config?
In classic ASP all Web site related information was stored in the metadata of IIS. This had the disadvantage that remote Web developers couldn't easily make Web-site configuration changes. For example, if you want to add a custom 404 error page, a setting needs to be made through the IIS admin tool, and you're Web host will likely charge you a flat fee to do this for you. With ASP.NET, however, these settings are moved into an XML-formatted text file (Web.config) that resides in the Web site's root directory. Through Web.config you can specify settings like custom 404 error pages, authentication and authorization settings for the Web sitempilation options for the ASP.NET Web pages, if tracing should be enabled, etc.
The Web.config file is an XML-formatted file. At the root level is the tag. Inside this tag you can add a number of other tags, the most common and useful one being the system.web tag, where you will specify most of the Web site configuration parameters. However, to specify application-wide settings you use the tag.
For example, if we wanted to add a database connection string parameter we could have a Web.config file like so.
What is the difference between ADO and ADO.NET?
ADO uses Recordsets and cursors to access and modify data. Because of its inherent design, Recordset can impact performance on the server side by tying up valuable resources. In addition, COM marshalling - an expensive data conversion process - is needed to transmit a Recordset. ADO.NET addresses three important needs that ADO doesn't address:
1. Providing a comprehensive disconnected data-access model, which is crucial to the Web environment
2. Providing tight integration with XML, and
3. Providing seamless integration with the .NET Framework (e.g., compatibility with the base class library's type system). From an ADO.NET implementation perspective, the Recordset object in ADO is eliminated in the .NET architecture. In its place, ADO.NET has several dedicated objects led by the DataSet object and including the DataAdapter, and DataReader objects to perform specific tasks. In addition, ADO.NET DataSets operate in disconnected state whereas the ADO RecordSet objects operated in a fully connected state.
In ADO, the in-memory representation of data is the RecordSet. In ADO.NET, it is the dataset. A RecordSet looks like a single table. If a RecordSet is to contain data from multiple database tables, it must use a JOIN query, which assembles the data from the various database tables into a single result table. In contrast, a dataset is a collection of one or more tables. The tables within a dataset are called data tables; specifically, they are DataTable objects. If a dataset contains data from multiple database tables, it will typically contain multiple DataTable objects. That is, each DataTable object typically corresponds to a single database table or view. In this way, a dataset can mimic the structure of the underlying database.
In ADO you scan sequentially through the rows of the RecordSet using the ADO MoveNext method. In ADO.NET, rows are represented as collections, so you can loop through a table as you would through any collection, or access particular rows via ordinal or primary key index. A cursor is a database element that controls record navigation, the ability to update data, and the visibility of changes made to the database by other users. ADO.NET does not have an inherent cursor object, but instead includes data classes that provide the functionality of a traditional cursor. For example, the functionality of a forward-only, read-only cursor is available in the ADO.NET DataReader object.
There is one significant difference between disconnected processing in ADO and ADO.NET. In ADO you communicate with the database by making calls to an OLE DB provider. In ADO.NET you communicate with the database through a data adapter (an OleDbDataAdapter, SqlDataAdapter, OdbcDataAdapter, or OracleDataAdapter object), which makes calls to an OLE DB provider or the APIs provided by the underlying data source.
Visual Basic .NET has many new and improved language features — such as inheritance, interfaces, and overloading that make it a powerful object-oriented programming language. As a Visual Basic developer, you can now create multithreaded, scalable applications using explicit multithreading. Other new language features in Visual Basic .NET include structured exception handling, custom attributes, and common language specification (CLS) compliance.
The CLS is a set of rules that standardizes such things as data types and how objects are exposed and interoperate. Visual Basic .NET adds several features that take advantage of the CLS. Any CLS-compliant language can use the classes, objects, and components you create in Visual Basic .NET. And you, as a Visual Basic user, can access classes, components, and objects from other CLS-compliant programming languages without worrying about language-specific differences such as data types.
CLS features used by Visual Basic .NET programs include assemblies, namespaces, and attributes.
These are the new features to be stated briefly:
Inheritance
Visual Basic .NET supports inheritance by allowing you to define classes that serve as the basis for derived classes. Derived classes inherit and can extend the properties and methods of the base class. They can also override inherited methods with new implementations. All classes created with Visual Basic .NET are inheritable by default. Because the forms you design are really classes, you can use inheritance to define new forms based on existing ones.
Exception Handling
Visual Basic .NET supports structured exception handling, using an enhanced version of the Try...Catch...Finally syntax supported by other languages such as C++.
Structured exception handling combines a modern control structure (similar to Select Case or While) with exceptions, protected blocks of code, and filters. Structured exception handling makes it easy to create and maintain programs with robust, comprehensive error handlers.
Overloading
Overloading is the ability to define properties, methods, or procedures that have the same name but use different data types. Overloaded procedures allow you to provide as many implementations as necessary to handle different kinds of data, while giving the appearance of a single, versatile procedure. Overriding Properties and Methods The Overrides keyword allows derived objects to override characteristics inherited from parent objects. Overridden members have the same arguments as the members inherited from the base class, but different implementations. A member's new implementation can call the original implementation in the parent class by preceding the member name with MyBase.
Constructors and Destructors
Constructors are procedures that control initialization of new instances of a class. Conversely, destructors are methods that free system resources when a class leaves scope or is set to Nothing. Visual Basic .NET supports constructors and destructors using the Sub New and Sub Finalize procedures.
Data Types
Visual Basic .NET introduces three new data types. The Char data type is an unsigned 16-bit quantity used to store Unicode characters. It is equivalent to the .NET Framework System. Char data type. The Short data type, a signed 16-bit integer, was named Integer in earlier versions of Visual Basic. The Decimal data type is a 96-bit signed integer scaled by a variable power of 10. In earlier versions of Visual Basic, it was available only within a Variant.
Interfaces
Interfaces describe the properties and methods of classes, but unlike classes, do not provide implementations. The Interface statement allows you to declare interfaces, while the Implements statement lets you write code that puts the items described in the interface into practice.
Delegates
Delegates objects that can call the methods of objects on your behalf are sometimes described as type-safe, object-oriented function pointers. You can use delegates to let procedures specify an event handler method that runs when an event occurs. You can also use delegates with multithreaded applications. For details, see Delegates and the AddressOf Operator.
Shared Members
Shared members are properties, procedures, and fields that are shared by all instances of a class. Shared data members are useful when multiple objects need to use information that is common to all. Shared class methods can be used without first creating an object from a class.
References
References allow you to use objects defined in other assemblies. In Visual Basic .NET, references point to assemblies instead of type libraries. For details, see References and the Imports Statement. Namespaces prevent naming conflicts by organizing classes, interfaces, and methods into hierarchies.
Assemblies
Assemblies replace and extend the capabilities of type libraries by, describing all the required files for a particular component or application. An assembly can contain one or more namespaces.
Attributes
Attributes enable you to provide additional information about program elements. For example, you can use an attribute to specify which methods in a class should be exposed when the class is used as a XML Web service.
Multithreading
Visual Basic .NET allows you to write applications that can perform multiple tasks independently. A task that has the potential of holding up other tasks can execute on a separate thread, a process known as multithreading. By causing complicated tasks to run on threads that are separate from your user interface, multithreading makes your applications more responsive to user input.
Using ActiveX Control in .Net
ActiveX control is a special type of COM component that supports a User Interface. Using ActiveX Control in your .Net Project is even easier than using COM component. They are bundled usually in .ocx files. Again a proxy assembly is made by .Net utility AxImp.exe (which we will see shortly) which your application (or client) uses as if it is a .Net control or assembly.
Making Proxy Assembly For ActiveX Control: First, a proxy assembly is made using AxImp.exe (acronym for ActiveX Import) by writing following command on Command Prompt:
C:> AxImp C:MyProjectsMyControl.ocx
This command will make two dlls, e.g., in case of above command
MyControl.dll
AxMyControl.dll
The first file MyControl.dll is a .Net assembly proxy, which allows you to reference the ActiveX as if it were non-graphical object.
The second file AxMyControl.dll is the Windows Control, which allows u to use the graphical aspects of activex control and use it in the Windows Form Project.
Adding Reference of ActiveX Proxy Assembly in your Project Settings: To add a reference of ActiveX Proxy Assembly in our Project, do this:
o Select Project A Add Reference (Select Add Reference from Project Menu).
o This will show you a dialog box, select .Net tab from the top of window.
o Click Browse button on the top right of window.
o Select the dll file for your ActiveX Proxy Assembly (which is MyControl.dll) and click OK o Your selected component is now shown in the ‘Selected Component’ List Box. Click OK again Some More On Using COM or ActiveX in .Net
.Net only provides wrapper class or proxy assembly (Runtime Callable Wrapper or RCW) for COM or activeX control. In the background, it is actually delegating the tasks to the original COM, so it does not convert your COM/activeX but just imports them.
A good thing about .Net is that when it imports a component, it also imports the components that are publically referenced by that component. So, if your component, say MyDataAcsess.dll references ADODB.dll then .Net will automatically import that COM component too!
The Visual Studio.NET does surprise you in a great deal when u see that it is applying its intellisense (showing methods, classes, interfaces, properties when placing dot) even on your imported COM components!!!! Isn’t it a magic or what?
When accessing thru RCW, .Net client has no knowledge that it is using COM component, it is presented just as another C# assembly.
U can also import COM component thru command prompt (for reference see Professional C# by Wrox)
U can also use your .Net components in COM, i.e., export your .net components (for reference see Professional C# by Wrox)
What is Machine.config?
Machine configuration file: The machine.config file contains settings that apply to the entire computer. This file is located in the %runtime install path%Config directory. There is only one machine.config file on a computer. The Machine.Config file found in the "CONFIG" subfolder of your .NET Framework install directory (c:WINNTMicrosoft.NETFramework{Version Number} CONFIG on Windows 2000 installations). The machine.config, which can be found in the directory $WINDIR$Microsoft.NETFrameworkv1.0.3705CONFIG, is an XML-formatted configuration file that specifies configuration options for the machine. This file contains, among many other XML elements, a browser Caps element. Inside this element are a number of other elements that specify parse rules for the various User-Agents, and what properties each of these parsing supports.
For example, to determine what platform is used, a filter element is used that specifies how to set the platform property based on what platform name is found in the User-Agent string. Specifically, the machine.config file contains:
platform=Win95
platform=Win98
platform=WinNT
...
That is, if in the User-Agent string the string "Windows 95" or "Win95" is found, the platform property is set to Win95. There are a number of filter elements in the browserCaps element in the machine.config file that define the various properties for various User-Agent strings.
Hence, when using the Request.Browser property to determine a user's browser features, the user's agent string is matched up to particular properties in the machine.config file. The ability for being able to detect a user's browser's capabilities, then, is based upon the honesty in the browser's sent User-Agent string. For example, Opera can be easily configured to send a User-Agent string that makes it appear as if it's IE 5.5. In this case from the Web server's perspective (and, hence, from your ASP.NET Web page's perspective), the user is visiting using IE 5.5, even though, in actuality, he is using Opera.
What is Web.config?
In classic ASP all Web site related information was stored in the metadata of IIS. This had the disadvantage that remote Web developers couldn't easily make Web-site configuration changes. For example, if you want to add a custom 404 error page, a setting needs to be made through the IIS admin tool, and you're Web host will likely charge you a flat fee to do this for you. With ASP.NET, however, these settings are moved into an XML-formatted text file (Web.config) that resides in the Web site's root directory. Through Web.config you can specify settings like custom 404 error pages, authentication and authorization settings for the Web sitempilation options for the ASP.NET Web pages, if tracing should be enabled, etc.
The Web.config file is an XML-formatted file. At the root level is the tag. Inside this tag you can add a number of other tags, the most common and useful one being the system.web tag, where you will specify most of the Web site configuration parameters. However, to specify application-wide settings you use the tag.
For example, if we wanted to add a database connection string parameter we could have a Web.config file like so.
What is the difference between ADO and ADO.NET?
ADO uses Recordsets and cursors to access and modify data. Because of its inherent design, Recordset can impact performance on the server side by tying up valuable resources. In addition, COM marshalling - an expensive data conversion process - is needed to transmit a Recordset. ADO.NET addresses three important needs that ADO doesn't address:
1. Providing a comprehensive disconnected data-access model, which is crucial to the Web environment
2. Providing tight integration with XML, and
3. Providing seamless integration with the .NET Framework (e.g., compatibility with the base class library's type system). From an ADO.NET implementation perspective, the Recordset object in ADO is eliminated in the .NET architecture. In its place, ADO.NET has several dedicated objects led by the DataSet object and including the DataAdapter, and DataReader objects to perform specific tasks. In addition, ADO.NET DataSets operate in disconnected state whereas the ADO RecordSet objects operated in a fully connected state.
In ADO, the in-memory representation of data is the RecordSet. In ADO.NET, it is the dataset. A RecordSet looks like a single table. If a RecordSet is to contain data from multiple database tables, it must use a JOIN query, which assembles the data from the various database tables into a single result table. In contrast, a dataset is a collection of one or more tables. The tables within a dataset are called data tables; specifically, they are DataTable objects. If a dataset contains data from multiple database tables, it will typically contain multiple DataTable objects. That is, each DataTable object typically corresponds to a single database table or view. In this way, a dataset can mimic the structure of the underlying database.
In ADO you scan sequentially through the rows of the RecordSet using the ADO MoveNext method. In ADO.NET, rows are represented as collections, so you can loop through a table as you would through any collection, or access particular rows via ordinal or primary key index. A cursor is a database element that controls record navigation, the ability to update data, and the visibility of changes made to the database by other users. ADO.NET does not have an inherent cursor object, but instead includes data classes that provide the functionality of a traditional cursor. For example, the functionality of a forward-only, read-only cursor is available in the ADO.NET DataReader object.
There is one significant difference between disconnected processing in ADO and ADO.NET. In ADO you communicate with the database by making calls to an OLE DB provider. In ADO.NET you communicate with the database through a data adapter (an OleDbDataAdapter, SqlDataAdapter, OdbcDataAdapter, or OracleDataAdapter object), which makes calls to an OLE DB provider or the APIs provided by the underlying data source.
.Net Interview Questions and Answers 6
What is the difference between VB and VB.NET?
Now VB.NET is object-oriented language. The following are some of the differences:
Data Type Changes
The .NET platform provides Common Type System to all the supported languages. This means that all the languages must support the same data types as enforced by common language runtime. This eliminates data type incompatibilities between various languages. For example on the 32-bit Windows platform, the integer data type takes 4 bytes in languages like C++ whereas in VB it takes 2 bytes. Following are the main changes related to data types in VB.NET:
. Under .NET the integer data type in VB.NET is also 4 bytes in size.
. VB.NET has no currency data type. Instead it provides decimal as a replacement.
. VB.NET introduces a new data type called Char. The char data type takes 2 bytes and can store Unicode characters.
. VB.NET do not have Variant data type. To achieve a result similar to variant type you can use Object data type. (Since every thing in .NET including primitive data types is an object, a variable of object type can point to any data type).
. In VB.NET there is no concept of fixed length strings.
. In VB6 we used the Type keyword to declare our user-defined structures. VB.NET introduces the structure keyword for the same purpose.
Declaring Variables
Consider this simple example in VB6:
Dim x,y as integer
In this example VB6 will consider x as variant and y as integer, which is somewhat odd behavior. VB.NET corrects this problem, creating both x and y as integers.
Furthermore, VB.NET allows you to assign initial values to the variables in the declaration statement itself:
br> Dim str1 as string = Hello
VB.NET also introduces Read-Only variables. Unlike constants Read-Only variables can be declared without initialization but once you assign a value to it, it cannot be changes.
Initialization here
Dim readonly x as integer
In later code
X=100
Now x can’t be changed
X=200 *********** Error **********
Property Syntax
In VB.NET, we anymore don't have separate declarations for Get and Set/Let. Now, everything is done in a single property declaration. This can be better explained by the following example.
Public [ReadOnly | WriteOnly] Property PropertyName as Datatype
Get
Return m_var
End Get
Set
M_var = value
End Set
End Property
Example:
Private _message as String
Public Property Message As String
Get
Return _message
End Get
Set
_message = Value
End Set
End Property
ByVal is the default - This is a crucial difference betwen VB 6.0 and VB.NET, where the default in VB 6.0 was by reference. But objects are still passed by reference.
Invoking Subroutines In previous versions of VB, only functions required the use of parentheses around the parameter list. But in VB.NET all function or subroutine calls require parentheses around the parameter list. This also applies, even though the parameter list is empty.
User-Defined Types - VB.NET does away with the keyword Type and replaces it with the keyword Structure
Public Structure Student
Dim strName as String
Dim strAge as Short
End Structure
Procedures and Functions
In VB6 all the procedure parameters are passed by reference (ByRef) by default. In VB.NET they are passed by value (ByVal) by default. Parantheses are required for calling procedures and functions whether they accept any parameters or not. In VB6 functions returned values using syntax like: FuntionName = return_value. In VB.NET you can use the Return keyword (Return return_value) to return values or you can continue to use the older syntax, which is still valid.
Scoping VB.NET now supports block-level scoping of variables. If your programs declare all of the variables at the beginning of the function or subroutine, this will not be a problem. However, the following VB 6.0 will cause an issue while upgrading to VB .NET
Do While objRs.Eof
Dim J as Integer
J=0
If objRs("flag")="Y" then
J=1
End If
objRs.MoveNext
Wend
If J Then
Msgbox "Flag is Y"
End If
In the above example the variable J will become out of scope just after the loop, since J was declared inside the While loop.
Exception Handling
The most wanted feature in earlier versions of VB was its error handling mechanism. The older versions relied on error handlers such as "On Error GoTo and On Error Resume Next. VB.NET provides us with a more stuructured approach. The new block structure allows us to track the exact error at the right time. The new error handling mechanism is refered to as Try...Throw...Catch...Finally. The following example will explain this new feature.
Sub myOpenFile()
Try
Open "myFile" For Output As #1
Write #1, myOutput
Catch
Kill "myFile"
Finally
Close #1
End try
End Sub
The keyword SET is gone - Since everything in VB.NET is an object. So the keyword SET is not at all used to differentiate between a simple variable assignment and an object assignment. So, if you have the following statement in VB 6.0
Set ObjConn = Nothing
Should be replaced as
ObjConn = Nothing.
Constructor and Destructor
The constructor procedure is one of the many new object-oriented features of VB.NET. The constructor in VB.NET replaces the Class_Initialize in VB 6.0. All occurance of Class_Initialize in previous versions of VB should now be placed in a class constructor. In VB.NET, a constructor is added to a class by adding a procedure called New. We can also create a class destructor, which is equivalent to Class_Terminate event in VB 6.0, by adding a sub-procedure called Finalize to our class. Usage of Return In VB.NET, we can use the keyword return to return a value from any function. In previous versions, we used to assign the value back with the help of the function name itself. The following example explains this:
Public Function Sum (intNum1 as Integer, intNum2 as Integer) as Integer
Dim intSum as Integer
intSum = intNum1 + intNum2
Return intSum
End Function
Static Methods
VB.NET now allows you to create static methods in your classes. Static methods are methods that can be called without requiring the developer to create instance of the class. For example, if you had a class named Foo with the non-static method NonStatic() and the static method Static(), you could call the Static() method like so:
Foo.Static()
However, non-static methods require than an instance of the class be created, like so:
Create an instance of the Foo class
Dim objFoo as New Foo()
Execute the NonStatic() method
ObjFoo.NonStatic()
To create a static method in a VB.NET, simply prefix the method definition with the keyword Shared.
What is a Strong Name?
A strong name consists of the assembly's identity its simple text name, version number, and culture information (if provided) plus a public key and a digital signature. It is generated from an assembly file (the file that contains the assembly manifest, which in turn contains the names and hashes of all the files that make up the assembly), using the corresponding private key. Assemblies with the same strong name are expected to be identical.
Strong names guarantee name uniqueness by relying on unique key pairs. No one can generate the same assembly name that you can, because an assembly generated with one private key has a different name than an assembly generated with another private key.
When you reference a strong-named assembly, you expect to get certain benefits, such as versioning and naming protection. If the strong-named assembly then references an assembly with a simple name, which does not have these benefits, you lose the benefits you would derive from using a strong-named assembly and revert to DLL conflicts. Therefore, strong-named assemblies can only reference other strong-named assemblies.
There are two ways to sign an assembly with a strong name:
1. Using the Assembly Linker (Al.exe) provided by the .NET Framework SDK.
2. Using assembly attributes to insert the strong name information in your code. You can use either the AssemblyKeyFileAttribute or the AssemblyKeyNameAttribute, depending on where the key file to be used is located.
To create and sign an assembly with a strong name using the Assembly Linker, at the command prompt, type the following command:
al /out: /keyfile:
In this command, assembly name is the name of the assembly to sign with a strong name, module name is the name of the code module used to create the assembly, and file name is the name of the container or file that contains the key pair.
The following example signs the assembly MyAssembly.dll with a strong name using the key file sgKey.snk.
al /out:MyAssembly.dll MyModule.netmodule /keyfile:sgKey.snk
To sign an assembly with a strong name using attributes
In a code module, add the AssemblyKeyFileAttribute or the AssemblyKeyNameAttribute, specifying the name of the file or container that contains the key pair to use when signing the assembly with a strong name. The following code example uses the AssemblyKeyFileAttribute with a key file called sgKey.snk.
[Visual Basic]
[C#]
[assembly:AssemblyKeyFileAttribute(@"....sgKey.snk")]
Now VB.NET is object-oriented language. The following are some of the differences:
Data Type Changes
The .NET platform provides Common Type System to all the supported languages. This means that all the languages must support the same data types as enforced by common language runtime. This eliminates data type incompatibilities between various languages. For example on the 32-bit Windows platform, the integer data type takes 4 bytes in languages like C++ whereas in VB it takes 2 bytes. Following are the main changes related to data types in VB.NET:
. Under .NET the integer data type in VB.NET is also 4 bytes in size.
. VB.NET has no currency data type. Instead it provides decimal as a replacement.
. VB.NET introduces a new data type called Char. The char data type takes 2 bytes and can store Unicode characters.
. VB.NET do not have Variant data type. To achieve a result similar to variant type you can use Object data type. (Since every thing in .NET including primitive data types is an object, a variable of object type can point to any data type).
. In VB.NET there is no concept of fixed length strings.
. In VB6 we used the Type keyword to declare our user-defined structures. VB.NET introduces the structure keyword for the same purpose.
Declaring Variables
Consider this simple example in VB6:
Dim x,y as integer
In this example VB6 will consider x as variant and y as integer, which is somewhat odd behavior. VB.NET corrects this problem, creating both x and y as integers.
Furthermore, VB.NET allows you to assign initial values to the variables in the declaration statement itself:
br> Dim str1 as string = Hello
VB.NET also introduces Read-Only variables. Unlike constants Read-Only variables can be declared without initialization but once you assign a value to it, it cannot be changes.
Initialization here
Dim readonly x as integer
In later code
X=100
Now x can’t be changed
X=200 *********** Error **********
Property Syntax
In VB.NET, we anymore don't have separate declarations for Get and Set/Let. Now, everything is done in a single property declaration. This can be better explained by the following example.
Public [ReadOnly | WriteOnly] Property PropertyName as Datatype
Get
Return m_var
End Get
Set
M_var = value
End Set
End Property
Example:
Private _message as String
Public Property Message As String
Get
Return _message
End Get
Set
_message = Value
End Set
End Property
ByVal is the default - This is a crucial difference betwen VB 6.0 and VB.NET, where the default in VB 6.0 was by reference. But objects are still passed by reference.
Invoking Subroutines In previous versions of VB, only functions required the use of parentheses around the parameter list. But in VB.NET all function or subroutine calls require parentheses around the parameter list. This also applies, even though the parameter list is empty.
User-Defined Types - VB.NET does away with the keyword Type and replaces it with the keyword Structure
Public Structure Student
Dim strName as String
Dim strAge as Short
End Structure
Procedures and Functions
In VB6 all the procedure parameters are passed by reference (ByRef) by default. In VB.NET they are passed by value (ByVal) by default. Parantheses are required for calling procedures and functions whether they accept any parameters or not. In VB6 functions returned values using syntax like: FuntionName = return_value. In VB.NET you can use the Return keyword (Return return_value) to return values or you can continue to use the older syntax, which is still valid.
Scoping VB.NET now supports block-level scoping of variables. If your programs declare all of the variables at the beginning of the function or subroutine, this will not be a problem. However, the following VB 6.0 will cause an issue while upgrading to VB .NET
Do While objRs.Eof
Dim J as Integer
J=0
If objRs("flag")="Y" then
J=1
End If
objRs.MoveNext
Wend
If J Then
Msgbox "Flag is Y"
End If
In the above example the variable J will become out of scope just after the loop, since J was declared inside the While loop.
Exception Handling
The most wanted feature in earlier versions of VB was its error handling mechanism. The older versions relied on error handlers such as "On Error GoTo and On Error Resume Next. VB.NET provides us with a more stuructured approach. The new block structure allows us to track the exact error at the right time. The new error handling mechanism is refered to as Try...Throw...Catch...Finally. The following example will explain this new feature.
Sub myOpenFile()
Try
Open "myFile" For Output As #1
Write #1, myOutput
Catch
Kill "myFile"
Finally
Close #1
End try
End Sub
The keyword SET is gone - Since everything in VB.NET is an object. So the keyword SET is not at all used to differentiate between a simple variable assignment and an object assignment. So, if you have the following statement in VB 6.0
Set ObjConn = Nothing
Should be replaced as
ObjConn = Nothing.
Constructor and Destructor
The constructor procedure is one of the many new object-oriented features of VB.NET. The constructor in VB.NET replaces the Class_Initialize in VB 6.0. All occurance of Class_Initialize in previous versions of VB should now be placed in a class constructor. In VB.NET, a constructor is added to a class by adding a procedure called New. We can also create a class destructor, which is equivalent to Class_Terminate event in VB 6.0, by adding a sub-procedure called Finalize to our class. Usage of Return In VB.NET, we can use the keyword return to return a value from any function. In previous versions, we used to assign the value back with the help of the function name itself. The following example explains this:
Public Function Sum (intNum1 as Integer, intNum2 as Integer) as Integer
Dim intSum as Integer
intSum = intNum1 + intNum2
Return intSum
End Function
Static Methods
VB.NET now allows you to create static methods in your classes. Static methods are methods that can be called without requiring the developer to create instance of the class. For example, if you had a class named Foo with the non-static method NonStatic() and the static method Static(), you could call the Static() method like so:
Foo.Static()
However, non-static methods require than an instance of the class be created, like so:
Create an instance of the Foo class
Dim objFoo as New Foo()
Execute the NonStatic() method
ObjFoo.NonStatic()
To create a static method in a VB.NET, simply prefix the method definition with the keyword Shared.
What is a Strong Name?
A strong name consists of the assembly's identity its simple text name, version number, and culture information (if provided) plus a public key and a digital signature. It is generated from an assembly file (the file that contains the assembly manifest, which in turn contains the names and hashes of all the files that make up the assembly), using the corresponding private key. Assemblies with the same strong name are expected to be identical.
Strong names guarantee name uniqueness by relying on unique key pairs. No one can generate the same assembly name that you can, because an assembly generated with one private key has a different name than an assembly generated with another private key.
When you reference a strong-named assembly, you expect to get certain benefits, such as versioning and naming protection. If the strong-named assembly then references an assembly with a simple name, which does not have these benefits, you lose the benefits you would derive from using a strong-named assembly and revert to DLL conflicts. Therefore, strong-named assemblies can only reference other strong-named assemblies.
There are two ways to sign an assembly with a strong name:
1. Using the Assembly Linker (Al.exe) provided by the .NET Framework SDK.
2. Using assembly attributes to insert the strong name information in your code. You can use either the AssemblyKeyFileAttribute or the AssemblyKeyNameAttribute, depending on where the key file to be used is located.
To create and sign an assembly with a strong name using the Assembly Linker, at the command prompt, type the following command:
al /out: /keyfile:
In this command, assembly name is the name of the assembly to sign with a strong name, module name is the name of the code module used to create the assembly, and file name is the name of the container or file that contains the key pair.
The following example signs the assembly MyAssembly.dll with a strong name using the key file sgKey.snk.
al /out:MyAssembly.dll MyModule.netmodule /keyfile:sgKey.snk
To sign an assembly with a strong name using attributes
In a code module, add the AssemblyKeyFileAttribute or the AssemblyKeyNameAttribute, specifying the name of the file or container that contains the key pair to use when signing the assembly with a strong name. The following code example uses the AssemblyKeyFileAttribute with a key file called sgKey.snk.
[Visual Basic]
[C#]
[assembly:AssemblyKeyFileAttribute(@"....sgKey.snk")]
.Net Interview Questions and Answers 5
What are the authentication methods in .NET?
There are 4 types of authentications.
1.WINDOWS AUTHENTICATION
2.FORMS AUTHENTICATION
3.PASSPORT AUTHENTICATION
4.NONE/CUSTOM AUTHENTICATION
The authentication option for the ASP.NET application is specified by using the tag in the Web.config file, as shown below:
other authentication options
1. WINDOWS AUTHENTICATION Schemes
I. Integrated Windows authentication
II. Basic and basic with SSL authentication
III. Digest authentication
IV. Client Certificate authentication
2. FORMS AUTHENTICATION
You, as a Web application developer, are supposed to develop the Web page and authenticate the user by checking the provided user ID and password against some user database
3.PASSPORT AUTHENTICATION
A centralized service provided by Microsoft, offers a single logon point for clients. Unauthenticated users are redirected to the Passport site
4 NONE/CUSTOM AUTHENTICATION:
If we don’t want ASP.NET to perform any authentication, we can set the authentication mode to “none”. The reason behind this decision could be: We don’t want to authenticate our users, and our Web site is open for all to use. We want to provide our own custom authentication
What is Serialization in .NET?
Anwer1
The serialization is the process of converting the objects into stream of bytes.
they or used for transport the objects(via remoting) and persist objects(via files and databases)
Answer2
When developing smaller applications that do not have a database (or other formal storage mechanism) or data that doesn’t need to be stored in a database (such as the state of a web application), you often still would like to save the data for later retrieval. There are many ways to do this, but many of them are subject to a lot of extra code (work) and extra time spent debugging. With .NET, there is now an easy way to add this functionality to your code with only a few lines of easily tested code. This easy way is called serialization.
Serialization is the process of storing an object, including all of its public and private fields, to a stream. Deserialization is the opposite – restoring an object’s field values from a stream. The stream is generally in the form of a FileStream, but does not have to be. It could be a memory stream or any other object that is of type IO.Stream. The format can be anything from XML to binary to SOAP.
What’s the use of System.Diagnostics.Process class?
By using System.Diagnostics.Process class, we can provide access to the files which are presented in the local and remote system.
Example: System.Diagnostics.Process(”c:\mlaks\example.txt”) — local file
System.Diagnostics.Process(”http://www.mlaks.com\example.txt”) — remote file
What are the authentication methods in .NET?
Abstract class: This class has abstract methods (no body). This class cannot be instantiated. One needs to provide the implementation of the methods by overriding them in the derived class. No Multiple Inheritance.
Interfaces: Interface class contains all abstract methods which are public by default. All of these methods must be implemented in the derived class. One can inherit from from more than one interface thus provides for Multiple Inheritance.
re-clarification of object based:
VB6 DOES support polymorphism and interface inheritance. It also supports the “Implements” keyword. What is not supported in vb6 is implementation inheritance.
Also, from above, vb6 DOES “provides access to third-party controls like COM, DCOM ” That is not anything new in .NET.
How to achieve Polymorphism in VB.Net?
We can achieve polymarphism in .Net i.e Compile time polymarphism and Runtime polymarphism. Compiletime Polymarphism achieved by method overloading. Runtime polymarphism achieved by Early Binding or Late Binding. Provide the function pointer to the object at compile time called as Early Binding.
provide the function pointer to the object at runtime called as Late Binding
class emp having the method display()
class dept having the method display()
create objects as in the main function
// Early binding
dim obj as new emp
dim ob as new dept
obj.display()-to call the display method of emp class
ob.display-to call the display method of the dept class
// Late binding
create object in the main class as
object obj
obj=new emp
obj.display()-to call the display of emp class
obj=new dept
obj.display()-to call the display of dept class
Difference between Class And Interface
Class is logical representation of object. It is collection of data and related sub procedures with defination.
Interface is also a class containg methods which is not having any definations.
Class does not support multiple inheritance. But interface can support.
What doesu mean by .NET framework?
The .NET Framework is an environment for building, deploying, and running Web Services and other applications. It consists of three main parts: the Common Language Runtime, the Framework classes, and ASP.NET
What is assembly?
It is a single deployable unit that contains all the information abt the implimentation of classes , stuctures and interfaces
What is namespaces?
It is a logical group of related classes and interfaces and that can be used byany language targeting the .net framework.
.NET framework programming interview questions
.NET framework overview
1. Has own class libraries. System is the main namespace and all other namespaces are subsets of this.
2. It has CLR(Common language runtime, Common type system, common language specification)
3. All the types are part of CTS and Object is the base class for all the types.
4. If a language said to be .net complaint, it should be compatible with CTS and CLS.
5. All the code compiled into an intermediate language by the .Net language compiler, which is nothing but an assembly.
6. During runtime, JIT of CLR picks the IL code and converts into PE machine code and from there it processes the request.
7. CTS, CLS, CLR
8. Garbage Collection
9. Dispose, finalize, suppress finalize, Idispose interface
10. Assemblies, Namespace: Assembly is a collection of class/namespaces. An assembly contains Manifest, Metadata, Resource files, IL code
11. Com interoperability, adding references, web references
12. Database connectivity and providers
Application Domain
1. Class modifiers: public, private, friend, protected, protected friend, mustinherit, NotInheritable
2. Method modifiers: public, private
3. Overridable
4. Shadows
5. Overloadable
6. Overrides
7. Overloads
8. Set/Get Property
9. IIF
10. Inheritance
11. Polymorphism
12. Delegates
13. Events
14. Reflection
15. Boxing
16. UnBoxing
ASP.Net
1. Web Controls: Data grid (templates, sorting, paging, bound columns, unbound columns, data binding), Data list, repeater controls
2. HTML Controls
3. Code behind pages, system.web.ui.page base class
4. Web.config: App settings, identity (impersonate), authentication (windows, forms, anonymous, passport), authorization
5. Databind.eval
6. Trace, Debug
7. Output cache
8. Session management
9. Application, Session
10. Global.asax httpapplication
11. User controls, custom controls, custom rendered controls (postback event, postdatachanged event) usercontrol is the base class
12. Directives
ADO.Net
1. Command object (ExecuteNonquery, ExecuteReader, ExecuteXMLReader, ExecuteScalar)
2. DataAdapter object (Fill)
3. Dataset (collection of tables)
4. CommandBuiler object
5. Transaction Object
6. Isolation levels
There are 4 types of authentications.
1.WINDOWS AUTHENTICATION
2.FORMS AUTHENTICATION
3.PASSPORT AUTHENTICATION
4.NONE/CUSTOM AUTHENTICATION
The authentication option for the ASP.NET application is specified by using the tag in the Web.config file, as shown below:
other authentication options
1. WINDOWS AUTHENTICATION Schemes
I. Integrated Windows authentication
II. Basic and basic with SSL authentication
III. Digest authentication
IV. Client Certificate authentication
2. FORMS AUTHENTICATION
You, as a Web application developer, are supposed to develop the Web page and authenticate the user by checking the provided user ID and password against some user database
3.PASSPORT AUTHENTICATION
A centralized service provided by Microsoft, offers a single logon point for clients. Unauthenticated users are redirected to the Passport site
4 NONE/CUSTOM AUTHENTICATION:
If we don’t want ASP.NET to perform any authentication, we can set the authentication mode to “none”. The reason behind this decision could be: We don’t want to authenticate our users, and our Web site is open for all to use. We want to provide our own custom authentication
What is Serialization in .NET?
Anwer1
The serialization is the process of converting the objects into stream of bytes.
they or used for transport the objects(via remoting) and persist objects(via files and databases)
Answer2
When developing smaller applications that do not have a database (or other formal storage mechanism) or data that doesn’t need to be stored in a database (such as the state of a web application), you often still would like to save the data for later retrieval. There are many ways to do this, but many of them are subject to a lot of extra code (work) and extra time spent debugging. With .NET, there is now an easy way to add this functionality to your code with only a few lines of easily tested code. This easy way is called serialization.
Serialization is the process of storing an object, including all of its public and private fields, to a stream. Deserialization is the opposite – restoring an object’s field values from a stream. The stream is generally in the form of a FileStream, but does not have to be. It could be a memory stream or any other object that is of type IO.Stream. The format can be anything from XML to binary to SOAP.
What’s the use of System.Diagnostics.Process class?
By using System.Diagnostics.Process class, we can provide access to the files which are presented in the local and remote system.
Example: System.Diagnostics.Process(”c:\mlaks\example.txt”) — local file
System.Diagnostics.Process(”http://www.mlaks.com\example.txt”) — remote file
What are the authentication methods in .NET?
Abstract class: This class has abstract methods (no body). This class cannot be instantiated. One needs to provide the implementation of the methods by overriding them in the derived class. No Multiple Inheritance.
Interfaces: Interface class contains all abstract methods which are public by default. All of these methods must be implemented in the derived class. One can inherit from from more than one interface thus provides for Multiple Inheritance.
re-clarification of object based:
VB6 DOES support polymorphism and interface inheritance. It also supports the “Implements” keyword. What is not supported in vb6 is implementation inheritance.
Also, from above, vb6 DOES “provides access to third-party controls like COM, DCOM ” That is not anything new in .NET.
How to achieve Polymorphism in VB.Net?
We can achieve polymarphism in .Net i.e Compile time polymarphism and Runtime polymarphism. Compiletime Polymarphism achieved by method overloading. Runtime polymarphism achieved by Early Binding or Late Binding. Provide the function pointer to the object at compile time called as Early Binding.
provide the function pointer to the object at runtime called as Late Binding
class emp having the method display()
class dept having the method display()
create objects as in the main function
// Early binding
dim obj as new emp
dim ob as new dept
obj.display()-to call the display method of emp class
ob.display-to call the display method of the dept class
// Late binding
create object in the main class as
object obj
obj=new emp
obj.display()-to call the display of emp class
obj=new dept
obj.display()-to call the display of dept class
Difference between Class And Interface
Class is logical representation of object. It is collection of data and related sub procedures with defination.
Interface is also a class containg methods which is not having any definations.
Class does not support multiple inheritance. But interface can support.
What doesu mean by .NET framework?
The .NET Framework is an environment for building, deploying, and running Web Services and other applications. It consists of three main parts: the Common Language Runtime, the Framework classes, and ASP.NET
What is assembly?
It is a single deployable unit that contains all the information abt the implimentation of classes , stuctures and interfaces
What is namespaces?
It is a logical group of related classes and interfaces and that can be used byany language targeting the .net framework.
.NET framework programming interview questions
.NET framework overview
1. Has own class libraries. System is the main namespace and all other namespaces are subsets of this.
2. It has CLR(Common language runtime, Common type system, common language specification)
3. All the types are part of CTS and Object is the base class for all the types.
4. If a language said to be .net complaint, it should be compatible with CTS and CLS.
5. All the code compiled into an intermediate language by the .Net language compiler, which is nothing but an assembly.
6. During runtime, JIT of CLR picks the IL code and converts into PE machine code and from there it processes the request.
7. CTS, CLS, CLR
8. Garbage Collection
9. Dispose, finalize, suppress finalize, Idispose interface
10. Assemblies, Namespace: Assembly is a collection of class/namespaces. An assembly contains Manifest, Metadata, Resource files, IL code
11. Com interoperability, adding references, web references
12. Database connectivity and providers
Application Domain
1. Class modifiers: public, private, friend, protected, protected friend, mustinherit, NotInheritable
2. Method modifiers: public, private
3. Overridable
4. Shadows
5. Overloadable
6. Overrides
7. Overloads
8. Set/Get Property
9. IIF
10. Inheritance
11. Polymorphism
12. Delegates
13. Events
14. Reflection
15. Boxing
16. UnBoxing
ASP.Net
1. Web Controls: Data grid (templates, sorting, paging, bound columns, unbound columns, data binding), Data list, repeater controls
2. HTML Controls
3. Code behind pages, system.web.ui.page base class
4. Web.config: App settings, identity (impersonate), authentication (windows, forms, anonymous, passport), authorization
5. Databind.eval
6. Trace, Debug
7. Output cache
8. Session management
9. Application, Session
10. Global.asax httpapplication
11. User controls, custom controls, custom rendered controls (postback event, postdatachanged event) usercontrol is the base class
12. Directives
ADO.Net
1. Command object (ExecuteNonquery, ExecuteReader, ExecuteXMLReader, ExecuteScalar)
2. DataAdapter object (Fill)
3. Dataset (collection of tables)
4. CommandBuiler object
5. Transaction Object
6. Isolation levels
.Net Interview Questions and Answers 4
What is "Microsoft Intermediate Language" (MSIL)?
A .NET programming language (C#, VB.NET, J# etc.) does not compile into executable code; instead it compiles into an intermediate code called Microsoft Intermediate Language (MSIL). As a programmer one need not worry about the syntax of MSIL - since our source code in automatically converted to MSIL. The MSIL code is then send to the CLR (Common Language Runtime) that converts the code to machine language, which is, then run on the host machine. MSIL is similar to Java Byte code. MSIL is the CPU-independent instruction set into which .NET Framework programs are compiled. It contains instructions for loading, storing, initializing, and calling methods on objects. Combined with metadata and the common type system, MSIL allows for true cross- language integration Prior to execution, MSIL is converted to machine code. It is not interpreted.
Differences between Datagrid, Datalist and Repeater?
1. Datagrid has paging while Datalist doesnt.
2. Datalist has a property called repeat. Direction = vertical/horizontal. (This is of great help in designing layouts). This is not there in Datagrid.
3. A repeater is used when more intimate control over html generation is required.
4. When only checkboxes/radiobuttons are repeatedly served then a checkboxlist or radiobuttonlist are used as they involve fewer overheads than a Datagrid.
The Repeater repeats a chunk of HTML you write, it has the least functionality of the three. DataList is the next step up from a Repeater; accept you have very little control over the HTML that the control renders. DataList is the first of the three controls that allow you Repeat-Columns horizontally or vertically. Finally, the DataGrid is the motherload. However, instead of working on a row-by-row basis, you’re working on a column-by-column basis. DataGrid caters to sorting and has basic paging for your disposal. Again you have little contro, over the HTML. NOTE: DataList and DataGrid both render as HTML tables by default. Out of the 3 controls, I use the Repeater the most due to its flexibility w/ HTML. Creating a Pagination scheme isn't that hard, so I rarely if ever use a DataGrid.
Occasionally I like using a DataList because it allows me to easily list out my records in rows of three for instance.
I am constantly writing the drawing procedures with System.Drawing.Graphics, but having to use the try and dispose blocks is too time-consuming with Graphics objects. Can I automate this?
Yes, the code
System.Drawing.Graphics canvas = new System.Drawing.Graphics();
try
{
//some code
}
finally
canvas.Dispose();
is functionally equivalent to
using (System.Drawing.Graphics canvas = new System.Drawing.Graphics())
{
//some code
} //canvas.Dispose() gets called automatically
How do you trigger the Paint event in System.Drawing?
Invalidate the current form, the OS will take care of repainting. The Update method forces the repaint.
With these events, why wouldn’t Microsoft combine Invalidate and Paint, so that you wouldn’t have to tell it to repaint, and then to force it to repaint?
Painting is the slowest thing the OS does, so usually telling it to repaint, but not forcing it allows for the process to take place in the background.
How can you assign an RGB color to a System.Drawing.Color object?
Call the static method FromArgb of this class and pass it the RGB values.
What class does Icon derive from? Isn’t it just a Bitmap with a wrapper name around it?
No, Icon lives in System.Drawing namespace. It’s not a Bitmap by default, and is treated separately by .NET. However, you can use ToBitmap method to get a valid Bitmap object from a valid Icon object.
Before in my VB app I would just load the icons from DLL. How can I load the icons provided by .NET dynamically?
By using System.Drawing.SystemIcons class, for example System.Drawing.SystemIcons.Warning produces an Icon with a warning sign in it.
When displaying fonts, what’s the difference between pixels, points and ems?
A pixel is the lowest-resolution dot the computer monitor supports. Its size depends on user’s settings and monitor size. A point is always 1/72 of an inch. An em is the number of pixels that it takes to display the letter M.
What is the difference between VB 6 and VB.NET?
Answer1
VB
1,Object-based Language
2,Doesnot support Threading
3,Not powerful Exception handling mechanism
4,Doesnot having support for the console based applications
5,Cannot use more than one version of com objects in vb application called DLL error
6,Doesnot support for the Disconnected data source.
VB.Net
1,Object-oriented Language
2,supports Threading
3,powerful Exception handling mechanism
4,having support for the console based applications
5,More than one version of dll is supported
6,supports the Disconnected data source by using Dataset class
Answer2
VB:
1. Object-based language
2. Does not support inheritance
3. ADO.Net does not give support for disconnected data architecture
4. No interoperability function
5. No support for threading
VB.Net
1. Object-Oriented Programming lanugage
2. ADO.Net gives support for disconnected data architecture
3. It provides interoperability
4. It uses managed code
5. supports threading
6. provides access to third-party controls like COM, DCOM
Answer2
1.The concept of the complete flow of execution of a program from start to finish: Visual Basic hides this aspect of programs from you, so that the only elements of a Visual Basic program you code are the event handlers and any methods in class modules. C# makes the complete program available to you as source code. The reason for this has to do with the fact that C# can be seen, philosophically, as next-generation C++. The roots of C++ go back to the 1960s and predate windowed user interfaces and sophisticated operating systems. C++ evolved as a low-level, closeto- the-machine, all-purpose language. To write GUI applications with C++ meant that you had to invoke the system calls to create and interact with the windowed forms. C# has been designed to build on this tradition while simplifying and modernizing C++, to combine the low-level performance benefits of C++ with the ease of coding in Visual Basic. Visual Basic, on the other hand, is designed specifically for rapid application development of Windows GUI applications. For this reason, in Visual Basic all the GUI boilerplate code is hidden, and all the Visual Basic programmer implements are the event handlers. In C# on the other hand, this boilerplate code is exposed as part of your source code.
2. Classes and inheritance: C# is a genuine object-oriented language, unlike Visual Basic, requiring all code to be a part of a class. It also includes extensive support for implementation inheritance. Indeed, most well-designed C# programs will be very much designed around this form of inheritance, which is completely absent in Visual Basic.
A .NET programming language (C#, VB.NET, J# etc.) does not compile into executable code; instead it compiles into an intermediate code called Microsoft Intermediate Language (MSIL). As a programmer one need not worry about the syntax of MSIL - since our source code in automatically converted to MSIL. The MSIL code is then send to the CLR (Common Language Runtime) that converts the code to machine language, which is, then run on the host machine. MSIL is similar to Java Byte code. MSIL is the CPU-independent instruction set into which .NET Framework programs are compiled. It contains instructions for loading, storing, initializing, and calling methods on objects. Combined with metadata and the common type system, MSIL allows for true cross- language integration Prior to execution, MSIL is converted to machine code. It is not interpreted.
Differences between Datagrid, Datalist and Repeater?
1. Datagrid has paging while Datalist doesnt.
2. Datalist has a property called repeat. Direction = vertical/horizontal. (This is of great help in designing layouts). This is not there in Datagrid.
3. A repeater is used when more intimate control over html generation is required.
4. When only checkboxes/radiobuttons are repeatedly served then a checkboxlist or radiobuttonlist are used as they involve fewer overheads than a Datagrid.
The Repeater repeats a chunk of HTML you write, it has the least functionality of the three. DataList is the next step up from a Repeater; accept you have very little control over the HTML that the control renders. DataList is the first of the three controls that allow you Repeat-Columns horizontally or vertically. Finally, the DataGrid is the motherload. However, instead of working on a row-by-row basis, you’re working on a column-by-column basis. DataGrid caters to sorting and has basic paging for your disposal. Again you have little contro, over the HTML. NOTE: DataList and DataGrid both render as HTML tables by default. Out of the 3 controls, I use the Repeater the most due to its flexibility w/ HTML. Creating a Pagination scheme isn't that hard, so I rarely if ever use a DataGrid.
Occasionally I like using a DataList because it allows me to easily list out my records in rows of three for instance.
I am constantly writing the drawing procedures with System.Drawing.Graphics, but having to use the try and dispose blocks is too time-consuming with Graphics objects. Can I automate this?
Yes, the code
System.Drawing.Graphics canvas = new System.Drawing.Graphics();
try
{
//some code
}
finally
canvas.Dispose();
is functionally equivalent to
using (System.Drawing.Graphics canvas = new System.Drawing.Graphics())
{
//some code
} //canvas.Dispose() gets called automatically
How do you trigger the Paint event in System.Drawing?
Invalidate the current form, the OS will take care of repainting. The Update method forces the repaint.
With these events, why wouldn’t Microsoft combine Invalidate and Paint, so that you wouldn’t have to tell it to repaint, and then to force it to repaint?
Painting is the slowest thing the OS does, so usually telling it to repaint, but not forcing it allows for the process to take place in the background.
How can you assign an RGB color to a System.Drawing.Color object?
Call the static method FromArgb of this class and pass it the RGB values.
What class does Icon derive from? Isn’t it just a Bitmap with a wrapper name around it?
No, Icon lives in System.Drawing namespace. It’s not a Bitmap by default, and is treated separately by .NET. However, you can use ToBitmap method to get a valid Bitmap object from a valid Icon object.
Before in my VB app I would just load the icons from DLL. How can I load the icons provided by .NET dynamically?
By using System.Drawing.SystemIcons class, for example System.Drawing.SystemIcons.Warning produces an Icon with a warning sign in it.
When displaying fonts, what’s the difference between pixels, points and ems?
A pixel is the lowest-resolution dot the computer monitor supports. Its size depends on user’s settings and monitor size. A point is always 1/72 of an inch. An em is the number of pixels that it takes to display the letter M.
What is the difference between VB 6 and VB.NET?
Answer1
VB
1,Object-based Language
2,Doesnot support Threading
3,Not powerful Exception handling mechanism
4,Doesnot having support for the console based applications
5,Cannot use more than one version of com objects in vb application called DLL error
6,Doesnot support for the Disconnected data source.
VB.Net
1,Object-oriented Language
2,supports Threading
3,powerful Exception handling mechanism
4,having support for the console based applications
5,More than one version of dll is supported
6,supports the Disconnected data source by using Dataset class
Answer2
VB:
1. Object-based language
2. Does not support inheritance
3. ADO.Net does not give support for disconnected data architecture
4. No interoperability function
5. No support for threading
VB.Net
1. Object-Oriented Programming lanugage
2. ADO.Net gives support for disconnected data architecture
3. It provides interoperability
4. It uses managed code
5. supports threading
6. provides access to third-party controls like COM, DCOM
Answer2
1.The concept of the complete flow of execution of a program from start to finish: Visual Basic hides this aspect of programs from you, so that the only elements of a Visual Basic program you code are the event handlers and any methods in class modules. C# makes the complete program available to you as source code. The reason for this has to do with the fact that C# can be seen, philosophically, as next-generation C++. The roots of C++ go back to the 1960s and predate windowed user interfaces and sophisticated operating systems. C++ evolved as a low-level, closeto- the-machine, all-purpose language. To write GUI applications with C++ meant that you had to invoke the system calls to create and interact with the windowed forms. C# has been designed to build on this tradition while simplifying and modernizing C++, to combine the low-level performance benefits of C++ with the ease of coding in Visual Basic. Visual Basic, on the other hand, is designed specifically for rapid application development of Windows GUI applications. For this reason, in Visual Basic all the GUI boilerplate code is hidden, and all the Visual Basic programmer implements are the event handlers. In C# on the other hand, this boilerplate code is exposed as part of your source code.
2. Classes and inheritance: C# is a genuine object-oriented language, unlike Visual Basic, requiring all code to be a part of a class. It also includes extensive support for implementation inheritance. Indeed, most well-designed C# programs will be very much designed around this form of inheritance, which is completely absent in Visual Basic.
.Net Interview Questions and Answers 3
.Net Interview Questions and Answers
What is the difference between a namespace and assembly name?
A namespace is a logical naming scheme for types in which a simple type name, such as MyType, is preceded with a dot-separated hierarchical name. Such a naming scheme is completely under control of the developer. For example, types MyCompany.FileAccess.A and MyCompany.FileAccess.B might be logically expected to have functionally related to file access. The .NET Framework uses a hierarchical naming scheme for grouping types into logical categories of related functionality, such as the ASP.NET application framework, or remoting functionality. Design tools can make use of namespaces to make it easier for developers to browse and reference types in their code. The concept of a namespace is not related to that of an assembly. A single assembly may contain types whose hierarchical names have different namespace roots, and a logical namespace root may span multiple assemblies. In the .NET Framework, a namespace is a logical design-time naming convenience, whereas an assembly establishes the name scope for types at run time.
What’s a Windows process?
It’s an application that’s running and had been allocated memory.
What’s typical about a Windows process in regards to memory allocation?
Each process is allocated its own block of available RAM space, no process can access another process’ code or data. If the process crashes, it dies alone without taking the entire OS or a bunch of other applications down.
Explain what relationship is between a Process, Application Domain, and Application?
Each process is allocated its own block of available RAM space, no process can access another process’ code or data. If the process crashes, it dies alone without taking the entire OS or a bunch of other applications down.
A process is an instance of a running application. An application is an executable on the hard drive or network. There can be numerous processes launched of the same application (5 copies of Word running), but 1 process can run just 1 application.
What are possible implementations of distributed applications in .NET?
.NET Remoting and ASP.NET Web Services. If we talk about the Framework Class Library, noteworthy classes are in System.Runtime.Remoting and System.Web.Services.
What are the consideration in deciding to use .NET Remoting or ASP.NET Web Services?
Remoting is a more efficient communication exchange when you can control both ends of the application involved in the communication process. Web Services provide an open-protocol-based exchange of information. Web Services are best when you need to communicate with an external organization or another (non-.NET) technology.
What’s a proxy of the server object in .NET Remoting?
It’s a fake copy of the server object that resides on the client side and behaves as if it was the server. It handles the communication between real server object and the client object. This process is also known as marshaling.
What are remotable objects in .NET Remoting?
Remotable objects are the objects that can be marshaled across the application domains. You can marshal by value, where a deep copy of the object is created and then passed to the receiver. You can also marshal by reference, where just a reference to an existing object is passed.
What are channels in .NET Remoting?
Channels represent the objects that transfer the other serialized objects from one application domain to another and from one computer to another, as well as one process to another on the same box. A channel must exist before an object can be transferred.
What security measures exist for .NET Remoting in System.Runtime.Remoting?
None. Security should be taken care of at the application level. Cryptography and other security techniques can be applied at application or server level.
What is a formatter?
A formatter is an object that is responsible for encoding and serializing data into messages on one end, and deserializing and decoding messages into data on the other end.
Choosing between HTTP and TCP for protocols and Binary and SOAP for formatters, what are the trade-offs?
Binary over TCP is the most effiecient, SOAP over HTTP is the most interoperable.
What’s SingleCall activation mode used for?
If the server object is instantiated for responding to just one single request, the request should be made in SingleCall mode.
What’s Singleton activation mode?
A single object is instantiated regardless of the number of clients accessing it. Lifetime of this object is determined by lifetime lease.
How do you define the lease of the object?
By implementing ILease interface when writing the class code.
Can you configure a .NET Remoting object via XML file?
Yes, via machine.config and application level .config file (or web.config in ASP.NET). Application-level XML settings take precedence over machine.config.
How can you automatically generate interface for the remotable object in .NET with Microsoft tools?
Use the Soapsuds tool.
What is Delegation?
A delegate acts like a strongly type function pointer. Delegates can invoke the methods that they reference without making explicit calls to those methods.
Delegate is an entity that is entrusted with the task of representation, assign or passing on information. In code sense, it means a Delegate is entrusted with a Method to report information back to it when a certain task (which the Method expects) is accomplished outside the Method's class.
What is the difference between a namespace and assembly name?
A namespace is a logical naming scheme for types in which a simple type name, such as MyType, is preceded with a dot-separated hierarchical name. Such a naming scheme is completely under control of the developer. For example, types MyCompany.FileAccess.A and MyCompany.FileAccess.B might be logically expected to have functionally related to file access. The .NET Framework uses a hierarchical naming scheme for grouping types into logical categories of related functionality, such as the ASP.NET application framework, or remoting functionality. Design tools can make use of namespaces to make it easier for developers to browse and reference types in their code. The concept of a namespace is not related to that of an assembly. A single assembly may contain types whose hierarchical names have different namespace roots, and a logical namespace root may span multiple assemblies. In the .NET Framework, a namespace is a logical design-time naming convenience, whereas an assembly establishes the name scope for types at run time.
What’s a Windows process?
It’s an application that’s running and had been allocated memory.
What’s typical about a Windows process in regards to memory allocation?
Each process is allocated its own block of available RAM space, no process can access another process’ code or data. If the process crashes, it dies alone without taking the entire OS or a bunch of other applications down.
Explain what relationship is between a Process, Application Domain, and Application?
Each process is allocated its own block of available RAM space, no process can access another process’ code or data. If the process crashes, it dies alone without taking the entire OS or a bunch of other applications down.
A process is an instance of a running application. An application is an executable on the hard drive or network. There can be numerous processes launched of the same application (5 copies of Word running), but 1 process can run just 1 application.
What are possible implementations of distributed applications in .NET?
.NET Remoting and ASP.NET Web Services. If we talk about the Framework Class Library, noteworthy classes are in System.Runtime.Remoting and System.Web.Services.
What are the consideration in deciding to use .NET Remoting or ASP.NET Web Services?
Remoting is a more efficient communication exchange when you can control both ends of the application involved in the communication process. Web Services provide an open-protocol-based exchange of information. Web Services are best when you need to communicate with an external organization or another (non-.NET) technology.
What’s a proxy of the server object in .NET Remoting?
It’s a fake copy of the server object that resides on the client side and behaves as if it was the server. It handles the communication between real server object and the client object. This process is also known as marshaling.
What are remotable objects in .NET Remoting?
Remotable objects are the objects that can be marshaled across the application domains. You can marshal by value, where a deep copy of the object is created and then passed to the receiver. You can also marshal by reference, where just a reference to an existing object is passed.
What are channels in .NET Remoting?
Channels represent the objects that transfer the other serialized objects from one application domain to another and from one computer to another, as well as one process to another on the same box. A channel must exist before an object can be transferred.
What security measures exist for .NET Remoting in System.Runtime.Remoting?
None. Security should be taken care of at the application level. Cryptography and other security techniques can be applied at application or server level.
What is a formatter?
A formatter is an object that is responsible for encoding and serializing data into messages on one end, and deserializing and decoding messages into data on the other end.
Choosing between HTTP and TCP for protocols and Binary and SOAP for formatters, what are the trade-offs?
Binary over TCP is the most effiecient, SOAP over HTTP is the most interoperable.
What’s SingleCall activation mode used for?
If the server object is instantiated for responding to just one single request, the request should be made in SingleCall mode.
What’s Singleton activation mode?
A single object is instantiated regardless of the number of clients accessing it. Lifetime of this object is determined by lifetime lease.
How do you define the lease of the object?
By implementing ILease interface when writing the class code.
Can you configure a .NET Remoting object via XML file?
Yes, via machine.config and application level .config file (or web.config in ASP.NET). Application-level XML settings take precedence over machine.config.
How can you automatically generate interface for the remotable object in .NET with Microsoft tools?
Use the Soapsuds tool.
What is Delegation?
A delegate acts like a strongly type function pointer. Delegates can invoke the methods that they reference without making explicit calls to those methods.
Delegate is an entity that is entrusted with the task of representation, assign or passing on information. In code sense, it means a Delegate is entrusted with a Method to report information back to it when a certain task (which the Method expects) is accomplished outside the Method's class.
dot net interview questions 2
What are Attributes?
Attributes are declarative tags in code that insert additional metadata into an assembly. There exist two types of attributes in the .NET Framework: Predefined attributes such as AssemblyVersion, which already exist and are accessed through the Runtime Classes; and custom attributes, which you write yourself by extending the System.Attribute class.
What are the Types of Assemblies?
Assemblies are of two types:
1. Private Assemblies
2. Shared Assemblies
Private Assemblies: The assembly is intended only for one application. The files of that assembly must be placed in the same folder as the application or in a sub folder. No other application will be able to make a call to this assembly. The advantage of having a private assembly is that, it makes naming the assembly very easy, since the developer need not worry about name clashes with other assemblies. As long as the assembly has a unique name within the concerned application, there won't be any problems.
Shared Assemblies: If the assembly is to be made into a Shared Assembly, then the naming conventions are very strict since it has to be unique across the entire system. The naming conventions should also take care of newer versions of the component being shipped. These are accomplished by giving the assembly a Shared Name. Then the assembly is placed in the global assembly cache, which is a folder in the file system reserved for shared assemblies.
What is an Intermediate language?
Assemblies are made up of IL code modules and the metadata that describes them. Although programs may be compiled via an IDE or the command line, in fact, they are simply translated into IL, not machine code. The actual machine code is not generated until the function that requires it is called. This is the just-in-time, or JIT, compilation feature of .NET. JIT compilation happens at runtime for a variety of reasons, one of the most ambitious being Microsoft's desire for cross-platform .NET adoption. If a CLR is built for another operating system (UNIX or Mac), the same assemblies will run in addition to the Microsoft platforms. The hope is that .NET assemblies are write-once-run-anywhere applications. This is a .NET feature that works behind-the-scenes, ensuring that developers are not limited to writing applications for one single line of products. No one has demonstrated whether or not this promise will ever truly materialize.
CTS/CLS
The MSIL Instruction Set Specification is included with the .NET SDK, along with the IL Assembly Language Programmers Reference. If a developer wants to write custom .NET programming languages, these are the necessary specifications and syntax. The CTS and CLS define the types and syntaxes that every .NET language needs to embrace. An application may not expose these features, but it must consider them when communicating through IL.
ASP.NET Authentication Providers and IIS Security
ASP.NET implements authentication using authentication providers, which are code modules that verify credentials and implement other security functionality such as cookie generation. ASP.NET supports the following three authentication providers:
Forms Authentication: Using this provider causes unauthenticated requests to be redirected to a specified HTML form using client side redirection. The user can then supply logon credentials, and post the form back to the server. If the application authenticates the request (using application-specific logic), ASP.NET issues a cookie that contains the credentials or a key for reacquiring the client identity. Subsequent requests are issued with the cookie in the request headers, which means that subsequent authentications are unnecessary.
Passport Authentication: This is a centralized authentication service provided by Microsoft that offers a single logon facility and membership services for participating sites. ASP.NET, in conjunction with the Microsoft® Passport software development kit (SDK), provides similar functionality as Forms Authentication to Passport users.
Windows Authentication: This provider utilizes the authentication capabilities of IIS. After IIS completes its authentication, ASP.NET uses the authenticated identity's token to authorize access.
To enable a specified authentication provider for an ASP.NET application, you must create an entry in the application's configuration file as follows:
// web.config file
What is the difference between ASP and ASP.NET?
ASP is interpreted. ASP.NET Compiled event base programming.
Control events for text button can be handled at client javascript only. Since we have server controls events can handle at server side.
More error handling.
ASP .NET has better language support, a large set of new controls and XML based components, and better user authentication.
ASP .NET provides increased performance by running compiled code.
ASP .NET code is not fully backward compatible with ASP.
ASP .NET also contains a new set of object oriented input controls, like programmable list boxes, validation controls. A new data grid control supports sorting, data paging, and everything you expect from a dataset control. The first request for an ASP.NET page on the server will compile the ASP .NET code and keep a cached copy in memory. The result of this is greatly increased performance.
ASP .NET is not fully compatible with earlier versions of ASP, so most of the old ASP code will need some changes to run under ASP .NET. To overcome this problem,
ASP .NET uses a new file extension ".aspx". This will make ASP .NET applications able to run side by side with standard ASP applications on the same server.
Using COM Component in .Net ?
As most of you know that .Net does not encourage the development of COM components and provides a different solution to making reusable components through Assemblies. But, there are a lot of COM components present which our .Net application might need to use. Fortunately, .Net provides an extremely simple approach to achieve this. This is achieved by using ‘Wrapper Classes’ and ‘Proxy Components’. .Net wraps the COM component into .Net assembly technically called ‘Runtime Callable Wrapper’ or RCW. Then u can call and use your COM component just as a .Net (or C#, if u are using C#) Assembly.
What is an assembly?
An assembly is the primary building block of a .NET Framework application. It is a collection of functionality that is built, versioned, and deployed as a single implementation unit (as one or more files). All managed types and resources are marked either as accessible only within their implementation unit, or as accessible by code outside that unit. .NET Assembly contains all the metadata about the modules, types, and other elements it contains in the form of a manifest. The CLR loves assemblies because differing programming languages are just perfect for creating certain kinds of applications. For example, COBOL stands for Common Business-Oriented Language because it’s tailor-made for creating business apps. However, it’s not much good for creating drafting programs. Regardless of what language you used to create your modules, they can all work together within one Portable Executable Assembly. There’s a hierarchy to the structure of .NET code. That hierarchy is Assembly - > Module -> Type -> Method." Assemblies can be static or dynamic. Static assemblies can include .NET Framework types (interfaces and classes), as well as resources for the assembly (bitmaps, JPEG files, resource files, and so on). Static assemblies are stored on disk in portable executable (PE) files. You can also use the .NET Framework to create dynamic assemblies, which are run directly from memory and are not saved to disk before execution. You can save dynamic assemblies to disk after they have executed.
What is a Web Service?
A web service is a software component that exposes itself through the open communication channels of the Internet. Applications running on remote machines, on potentially different platforms, can access these components in a language and platform-independent manner. A Web Service is a group of functions, packaged together for use in a common framework throughout a network.
webFarm Vs webGardens
A web farm is a multi-server scenario. So we may have a server in each state of US. If the load on one server is in excess then the other servers step in to bear the brunt.
How they bear it is based on various models.
1. RoundRobin. (All servers share load equally)
2. NLB (economical)
3. HLB (expensive but can scale up to 8192 servers)
4. Hybrid (of 2 and 3).
5. CLB (Component load balancer).
A web garden is a multi-processor setup. i.e., a single server (not like the multi server above).
How to implement webfarms in .Net:
Go to web.config and Here for mode = you have 4 options.
a) Say mode=inproc (non web farm but fast when you have very few customers).
b) Say mode=StateServer (for webfarm)
c) Say mode=SqlServer (for webfarm)
Whether to use option b or c depends on situation. StateServer is faster but SqlServer is more reliable and used for mission critical applications.
How to use webgardens in .Net:
Go to web.config and Change the false to true. You have one more attribute that is related to webgarden in the same tag called cpuMask.
Attributes are declarative tags in code that insert additional metadata into an assembly. There exist two types of attributes in the .NET Framework: Predefined attributes such as AssemblyVersion, which already exist and are accessed through the Runtime Classes; and custom attributes, which you write yourself by extending the System.Attribute class.
What are the Types of Assemblies?
Assemblies are of two types:
1. Private Assemblies
2. Shared Assemblies
Private Assemblies: The assembly is intended only for one application. The files of that assembly must be placed in the same folder as the application or in a sub folder. No other application will be able to make a call to this assembly. The advantage of having a private assembly is that, it makes naming the assembly very easy, since the developer need not worry about name clashes with other assemblies. As long as the assembly has a unique name within the concerned application, there won't be any problems.
Shared Assemblies: If the assembly is to be made into a Shared Assembly, then the naming conventions are very strict since it has to be unique across the entire system. The naming conventions should also take care of newer versions of the component being shipped. These are accomplished by giving the assembly a Shared Name. Then the assembly is placed in the global assembly cache, which is a folder in the file system reserved for shared assemblies.
What is an Intermediate language?
Assemblies are made up of IL code modules and the metadata that describes them. Although programs may be compiled via an IDE or the command line, in fact, they are simply translated into IL, not machine code. The actual machine code is not generated until the function that requires it is called. This is the just-in-time, or JIT, compilation feature of .NET. JIT compilation happens at runtime for a variety of reasons, one of the most ambitious being Microsoft's desire for cross-platform .NET adoption. If a CLR is built for another operating system (UNIX or Mac), the same assemblies will run in addition to the Microsoft platforms. The hope is that .NET assemblies are write-once-run-anywhere applications. This is a .NET feature that works behind-the-scenes, ensuring that developers are not limited to writing applications for one single line of products. No one has demonstrated whether or not this promise will ever truly materialize.
CTS/CLS
The MSIL Instruction Set Specification is included with the .NET SDK, along with the IL Assembly Language Programmers Reference. If a developer wants to write custom .NET programming languages, these are the necessary specifications and syntax. The CTS and CLS define the types and syntaxes that every .NET language needs to embrace. An application may not expose these features, but it must consider them when communicating through IL.
ASP.NET Authentication Providers and IIS Security
ASP.NET implements authentication using authentication providers, which are code modules that verify credentials and implement other security functionality such as cookie generation. ASP.NET supports the following three authentication providers:
Forms Authentication: Using this provider causes unauthenticated requests to be redirected to a specified HTML form using client side redirection. The user can then supply logon credentials, and post the form back to the server. If the application authenticates the request (using application-specific logic), ASP.NET issues a cookie that contains the credentials or a key for reacquiring the client identity. Subsequent requests are issued with the cookie in the request headers, which means that subsequent authentications are unnecessary.
Passport Authentication: This is a centralized authentication service provided by Microsoft that offers a single logon facility and membership services for participating sites. ASP.NET, in conjunction with the Microsoft® Passport software development kit (SDK), provides similar functionality as Forms Authentication to Passport users.
Windows Authentication: This provider utilizes the authentication capabilities of IIS. After IIS completes its authentication, ASP.NET uses the authenticated identity's token to authorize access.
To enable a specified authentication provider for an ASP.NET application, you must create an entry in the application's configuration file as follows:
// web.config file
What is the difference between ASP and ASP.NET?
ASP is interpreted. ASP.NET Compiled event base programming.
Control events for text button can be handled at client javascript only. Since we have server controls events can handle at server side.
More error handling.
ASP .NET has better language support, a large set of new controls and XML based components, and better user authentication.
ASP .NET provides increased performance by running compiled code.
ASP .NET code is not fully backward compatible with ASP.
ASP .NET also contains a new set of object oriented input controls, like programmable list boxes, validation controls. A new data grid control supports sorting, data paging, and everything you expect from a dataset control. The first request for an ASP.NET page on the server will compile the ASP .NET code and keep a cached copy in memory. The result of this is greatly increased performance.
ASP .NET is not fully compatible with earlier versions of ASP, so most of the old ASP code will need some changes to run under ASP .NET. To overcome this problem,
ASP .NET uses a new file extension ".aspx". This will make ASP .NET applications able to run side by side with standard ASP applications on the same server.
Using COM Component in .Net ?
As most of you know that .Net does not encourage the development of COM components and provides a different solution to making reusable components through Assemblies. But, there are a lot of COM components present which our .Net application might need to use. Fortunately, .Net provides an extremely simple approach to achieve this. This is achieved by using ‘Wrapper Classes’ and ‘Proxy Components’. .Net wraps the COM component into .Net assembly technically called ‘Runtime Callable Wrapper’ or RCW. Then u can call and use your COM component just as a .Net (or C#, if u are using C#) Assembly.
What is an assembly?
An assembly is the primary building block of a .NET Framework application. It is a collection of functionality that is built, versioned, and deployed as a single implementation unit (as one or more files). All managed types and resources are marked either as accessible only within their implementation unit, or as accessible by code outside that unit. .NET Assembly contains all the metadata about the modules, types, and other elements it contains in the form of a manifest. The CLR loves assemblies because differing programming languages are just perfect for creating certain kinds of applications. For example, COBOL stands for Common Business-Oriented Language because it’s tailor-made for creating business apps. However, it’s not much good for creating drafting programs. Regardless of what language you used to create your modules, they can all work together within one Portable Executable Assembly. There’s a hierarchy to the structure of .NET code. That hierarchy is Assembly - > Module -> Type -> Method." Assemblies can be static or dynamic. Static assemblies can include .NET Framework types (interfaces and classes), as well as resources for the assembly (bitmaps, JPEG files, resource files, and so on). Static assemblies are stored on disk in portable executable (PE) files. You can also use the .NET Framework to create dynamic assemblies, which are run directly from memory and are not saved to disk before execution. You can save dynamic assemblies to disk after they have executed.
What is a Web Service?
A web service is a software component that exposes itself through the open communication channels of the Internet. Applications running on remote machines, on potentially different platforms, can access these components in a language and platform-independent manner. A Web Service is a group of functions, packaged together for use in a common framework throughout a network.
webFarm Vs webGardens
A web farm is a multi-server scenario. So we may have a server in each state of US. If the load on one server is in excess then the other servers step in to bear the brunt.
How they bear it is based on various models.
1. RoundRobin. (All servers share load equally)
2. NLB (economical)
3. HLB (expensive but can scale up to 8192 servers)
4. Hybrid (of 2 and 3).
5. CLB (Component load balancer).
A web garden is a multi-processor setup. i.e., a single server (not like the multi server above).
How to implement webfarms in .Net:
Go to web.config and Here for mode = you have 4 options.
a) Say mode=inproc (non web farm but fast when you have very few customers).
b) Say mode=StateServer (for webfarm)
c) Say mode=SqlServer (for webfarm)
Whether to use option b or c depends on situation. StateServer is faster but SqlServer is more reliable and used for mission critical applications.
How to use webgardens in .Net:
Go to web.config and Change the false to true. You have one more attribute that is related to webgarden in the same tag called cpuMask.
.Net Interview Questions and Answers 1
What is a Manifest?
An assembly manifest contains all the metadata needed to specify the assembly's version requirements and security identity, and all metadata needed to define the scope of the assembly and resolve references to resources and classes. The assembly manifest can be stored in either a PE (Portable Executable) file (an .exe or .dll) with Microsoft intermediate language (MSIL) code or in a standalone PE (Portable Executable) file that contains only assembly manifest information. The following table shows the information contained in the assembly manifest. The first four items the assembly name, version number, culture, and strong name information make up the assembly's identity.
Assembly name: A text string specifying the assembly's name.
Version number: A major and minor version number, and a revision and build number. The common language runtime uses these numbers to enforce version policy.
Culture: Information on the culture or language the assembly supports. This information should be used only to designate an assembly as a satellite assembly containing culture- or language-specific information. (An assembly with culture information is automatically assumed to be a satellite assembly.) Strong name information: The public key from the publisher if the assembly has been given a strong name. List of all files in the assembly:
A hash of each file contained in the assembly and a file name. Note that all files that make up the assembly must be in the same directory as the file containing the assembly manifest.
Type reference information: Information used by the runtime to map a type reference to the file that contains its declaration and implementation. This is used for types that are exported from the assembly.
Information on referenced assemblies: A list of other assemblies that are statically referenced by the assembly. Each reference includes the dependent assembly's name, assembly metadata (version, culture, operating system, and so on), and public key, if the assembly is strong named.
Creating a Key Pair?
You can create a key pair using the Strong Name tool (Sn.exe). Key pair files usually have an .snk extension. To create a key pair At the command prompt, type the following command:
sn k
In this command, file name is the name of the output file containing the key pair. The following example creates a key pair called sgKey.snk.
sn -k sgKey.snk
What is the difference between "using System.Data;" and directly adding the reference from "Add References Dialog Box"?
When u compile a program using command line, u add the references using /r switch. When you compile a program using Visual Studio, it adds those references to our assembly, which are added using "Add Reference" dialog box. While "using" statement facilitates us to use classes without using their fully qualified names.
For example: if u have added a reference to "System.Data.SqlClient" using "Add Reference" dialog box then u can use SqlConnection class like this:
System.Data.SqlClient.SqlConnection
But if u add a "using System.Data.SqlClient" statement at the start of ur code then u can directly use SqlConnection class.
On the other hand if u add a reference using "using System.Data.SqlClient" statement, but don't add it using "Add Reference" dialog box, Visual Studio will give error message while we compile the program.
What is GAC?
The global assembly cache stores assemblies specifically designated to be shared by several applications on the computer. You should share assemblies by installing them into the global assembly cache only when you need to. Assemblies deployed in the global assembly cache must have a strong name. When an assembly is added to the global assembly cache, integrity checks are performed on all files that make up the assembly. The cache performs these integrity checks to ensure that an assembly has not been tampered with, for example, when a file has changed but the manifest does not reflect the change. Use a developer tool called the Global Assembly Cache tool (Gacutil.exe), provided by the .NET Framework SDK or Use Windows Explorer to drag assemblies into the cache. To install a strong-named assembly into the global assembly cache At the command prompt, type the following command:
gacutil I
In this command, assembly name is the name of the assembly to install in the global assembly cache.
What is a Metadata?
Metadata is information about a PE. In COM, metadata is communicated through non-standardized type libraries.
In .NET, this data is contained in the header portion of a COFF-compliant PE and follows certain guidelines;
it contains information such as the assembly’s name, version, language (spoken, not computera.k.a., culture), what external types are referenced, what internal types are exposed, methods, properties, classes, and much more.
The CLR uses metadata for a number of specific purposes. Security is managed through a public key in the PE’s header.
Information about classes, modules, and so forth allows the CLR to know in advance what structures are necessary. The class loader component of the CLR uses metadata to locate specific classes within assemblies, either locally or across networks.
Just-in-time (JIT) compilers use the metadata to turn IL into executable code.
Other programs take advantage of metadata as well.
A common example is placing a Microsoft Word document on a Windows 2000 desktop. If the document file has completed comments, author, title, or other Properties metadata, the text is displayed as a tool tip when a user hovers the mouse over the document on the desktop. You can use the Ildasm.exe utility to view the metadata in a PE. Literally, this tool is an IL disassembler.
What is managed code and managed data?
Managed code is code that is written to target the services of the Common Language Runtime.
In order to target these services, the code must provide a minimum level of information (metadata) to the runtime.
All C#, Visual Basic .NET, and JScript .NET code is managed by default.
Visual Studio .NET C++ code is not managed by default, but the compiler can produce managed code by specifying a command-line switch (/CLR).
Closely related to managed code is managed data--data that is allocated and de- allocated by the Common Language Runtime's garbage collector. C#, Visual Basic, and JScript .NET data is managed by default.
C# data can, however, be marked as unmanaged through the use of special keywords.
Visual Studio .NET C++ data is unmanaged by default (even when using the /CLR switch), but when using Managed Extensions for C++, a class can be marked as managed using the __gc keyword. As the name suggests, this means that the memory for instances of the class is managed by the garbage collector.
In addition, the class becomes a full participating member of the .NET Framework community, with the benefits and restrictions that it brings. An example of a benefit is proper interoperability with classes written in other languages (for example, a managed C++ class can inherit from a Visual Basic class).
An example of a restriction is that a managed class can only inherit from one base class.
What is .NET / .NET Framework?
It is a Framework in which Windows applications may be developed and run. The Microsoft .NET Framework is a platform for building, deploying, and running Web Services and applications. It provides a highly productive, standards-based, multi-language environment for integrating existing investments with next-generation applications and services as well as the agility to solve the challenges of deployment and operation of Internet-scale applications. The .NET Framework consists of three main parts: the common language runtime, a hierarchical set of unified class libraries, and a componentized version of Active Server Pages called ASP.NET. The .NET Framework provides a new programming model and rich set of classes designed to simplify application development for Windows, the Web, and mobile devices. It provides full support for XML Web services, contains robust security features, and delivers new levels of programming power. The .NET Framework is used by all Microsoft languages including Visual C#, Visual J#, and Visual C++.
What is Reflection?
It extends the benefits of metadata by allowing developers to inspect and use it at runtime. For example, dynamically determine all the classes contained in a given assembly and invoke their methods. Reflection provides objects that encapsulate assemblies, modules, and types. You can use reflection to dynamically create an instance of a type, bind the type to an existing object, or get the type from an existing object. You can then invoke the type's methods or access its fields and properties. Namespace: System.Reflection
What is "Common Type System" (CTS)?
CTS defines all of the basic types that can be used in the .NET Framework and the operations performed on those type.
All this time we have been talking about language interoperability, and .NET Class Framework. None of this is possible without all the language sharing the same data types. What this means is that an int should mean the same in VB, VC++, C# and all other .NET compliant languages. This is achieved through introduction of Common Type System (CTS).
What is "Common Language Specification" (CLS)?
CLS is the collection of the rules and constraints that every language (that seeks to achieve .NET compatibility) must follow. It is a subsection of CTS and it specifies how it shares and extends one another libraries.
What is "Common Language Runtime" (CLR)?
CLR is .NET equivalent of Java Virtual Machine (JVM). It is the runtime that converts a MSIL code into the host machine language code, which is then executed appropriately. The CLR is the execution engine for .NET Framework applications. It provides a number of services, including:
- Code management (loading and execution)
- Application memory isolation
- Verification of type safety
- Conversion of IL to native code.
- Access to metadata (enhanced type information)
- Managing memory for managed objects
- Enforcement of code access security
- Exception handling, including cross-language exceptions
- Interoperation between managed code, COM objects, and pre-existing DLL's (unmanaged code and data)
- Automation of object layout
- Support for developer services (profiling, debugging, and so on).
An assembly manifest contains all the metadata needed to specify the assembly's version requirements and security identity, and all metadata needed to define the scope of the assembly and resolve references to resources and classes. The assembly manifest can be stored in either a PE (Portable Executable) file (an .exe or .dll) with Microsoft intermediate language (MSIL) code or in a standalone PE (Portable Executable) file that contains only assembly manifest information. The following table shows the information contained in the assembly manifest. The first four items the assembly name, version number, culture, and strong name information make up the assembly's identity.
Assembly name: A text string specifying the assembly's name.
Version number: A major and minor version number, and a revision and build number. The common language runtime uses these numbers to enforce version policy.
Culture: Information on the culture or language the assembly supports. This information should be used only to designate an assembly as a satellite assembly containing culture- or language-specific information. (An assembly with culture information is automatically assumed to be a satellite assembly.) Strong name information: The public key from the publisher if the assembly has been given a strong name. List of all files in the assembly:
A hash of each file contained in the assembly and a file name. Note that all files that make up the assembly must be in the same directory as the file containing the assembly manifest.
Type reference information: Information used by the runtime to map a type reference to the file that contains its declaration and implementation. This is used for types that are exported from the assembly.
Information on referenced assemblies: A list of other assemblies that are statically referenced by the assembly. Each reference includes the dependent assembly's name, assembly metadata (version, culture, operating system, and so on), and public key, if the assembly is strong named.
Creating a Key Pair?
You can create a key pair using the Strong Name tool (Sn.exe). Key pair files usually have an .snk extension. To create a key pair At the command prompt, type the following command:
sn k
In this command, file name is the name of the output file containing the key pair. The following example creates a key pair called sgKey.snk.
sn -k sgKey.snk
What is the difference between "using System.Data;" and directly adding the reference from "Add References Dialog Box"?
When u compile a program using command line, u add the references using /r switch. When you compile a program using Visual Studio, it adds those references to our assembly, which are added using "Add Reference" dialog box. While "using" statement facilitates us to use classes without using their fully qualified names.
For example: if u have added a reference to "System.Data.SqlClient" using "Add Reference" dialog box then u can use SqlConnection class like this:
System.Data.SqlClient.SqlConnection
But if u add a "using System.Data.SqlClient" statement at the start of ur code then u can directly use SqlConnection class.
On the other hand if u add a reference using "using System.Data.SqlClient" statement, but don't add it using "Add Reference" dialog box, Visual Studio will give error message while we compile the program.
What is GAC?
The global assembly cache stores assemblies specifically designated to be shared by several applications on the computer. You should share assemblies by installing them into the global assembly cache only when you need to. Assemblies deployed in the global assembly cache must have a strong name. When an assembly is added to the global assembly cache, integrity checks are performed on all files that make up the assembly. The cache performs these integrity checks to ensure that an assembly has not been tampered with, for example, when a file has changed but the manifest does not reflect the change. Use a developer tool called the Global Assembly Cache tool (Gacutil.exe), provided by the .NET Framework SDK or Use Windows Explorer to drag assemblies into the cache. To install a strong-named assembly into the global assembly cache At the command prompt, type the following command:
gacutil I
In this command, assembly name is the name of the assembly to install in the global assembly cache.
What is a Metadata?
Metadata is information about a PE. In COM, metadata is communicated through non-standardized type libraries.
In .NET, this data is contained in the header portion of a COFF-compliant PE and follows certain guidelines;
it contains information such as the assembly’s name, version, language (spoken, not computera.k.a., culture), what external types are referenced, what internal types are exposed, methods, properties, classes, and much more.
The CLR uses metadata for a number of specific purposes. Security is managed through a public key in the PE’s header.
Information about classes, modules, and so forth allows the CLR to know in advance what structures are necessary. The class loader component of the CLR uses metadata to locate specific classes within assemblies, either locally or across networks.
Just-in-time (JIT) compilers use the metadata to turn IL into executable code.
Other programs take advantage of metadata as well.
A common example is placing a Microsoft Word document on a Windows 2000 desktop. If the document file has completed comments, author, title, or other Properties metadata, the text is displayed as a tool tip when a user hovers the mouse over the document on the desktop. You can use the Ildasm.exe utility to view the metadata in a PE. Literally, this tool is an IL disassembler.
What is managed code and managed data?
Managed code is code that is written to target the services of the Common Language Runtime.
In order to target these services, the code must provide a minimum level of information (metadata) to the runtime.
All C#, Visual Basic .NET, and JScript .NET code is managed by default.
Visual Studio .NET C++ code is not managed by default, but the compiler can produce managed code by specifying a command-line switch (/CLR).
Closely related to managed code is managed data--data that is allocated and de- allocated by the Common Language Runtime's garbage collector. C#, Visual Basic, and JScript .NET data is managed by default.
C# data can, however, be marked as unmanaged through the use of special keywords.
Visual Studio .NET C++ data is unmanaged by default (even when using the /CLR switch), but when using Managed Extensions for C++, a class can be marked as managed using the __gc keyword. As the name suggests, this means that the memory for instances of the class is managed by the garbage collector.
In addition, the class becomes a full participating member of the .NET Framework community, with the benefits and restrictions that it brings. An example of a benefit is proper interoperability with classes written in other languages (for example, a managed C++ class can inherit from a Visual Basic class).
An example of a restriction is that a managed class can only inherit from one base class.
What is .NET / .NET Framework?
It is a Framework in which Windows applications may be developed and run. The Microsoft .NET Framework is a platform for building, deploying, and running Web Services and applications. It provides a highly productive, standards-based, multi-language environment for integrating existing investments with next-generation applications and services as well as the agility to solve the challenges of deployment and operation of Internet-scale applications. The .NET Framework consists of three main parts: the common language runtime, a hierarchical set of unified class libraries, and a componentized version of Active Server Pages called ASP.NET. The .NET Framework provides a new programming model and rich set of classes designed to simplify application development for Windows, the Web, and mobile devices. It provides full support for XML Web services, contains robust security features, and delivers new levels of programming power. The .NET Framework is used by all Microsoft languages including Visual C#, Visual J#, and Visual C++.
What is Reflection?
It extends the benefits of metadata by allowing developers to inspect and use it at runtime. For example, dynamically determine all the classes contained in a given assembly and invoke their methods. Reflection provides objects that encapsulate assemblies, modules, and types. You can use reflection to dynamically create an instance of a type, bind the type to an existing object, or get the type from an existing object. You can then invoke the type's methods or access its fields and properties. Namespace: System.Reflection
What is "Common Type System" (CTS)?
CTS defines all of the basic types that can be used in the .NET Framework and the operations performed on those type.
All this time we have been talking about language interoperability, and .NET Class Framework. None of this is possible without all the language sharing the same data types. What this means is that an int should mean the same in VB, VC++, C# and all other .NET compliant languages. This is achieved through introduction of Common Type System (CTS).
What is "Common Language Specification" (CLS)?
CLS is the collection of the rules and constraints that every language (that seeks to achieve .NET compatibility) must follow. It is a subsection of CTS and it specifies how it shares and extends one another libraries.
What is "Common Language Runtime" (CLR)?
CLR is .NET equivalent of Java Virtual Machine (JVM). It is the runtime that converts a MSIL code into the host machine language code, which is then executed appropriately. The CLR is the execution engine for .NET Framework applications. It provides a number of services, including:
- Code management (loading and execution)
- Application memory isolation
- Verification of type safety
- Conversion of IL to native code.
- Access to metadata (enhanced type information)
- Managing memory for managed objects
- Enforcement of code access security
- Exception handling, including cross-language exceptions
- Interoperation between managed code, COM objects, and pre-existing DLL's (unmanaged code and data)
- Automation of object layout
- Support for developer services (profiling, debugging, and so on).
Interview questions for .NET
1. What is a static class?
2. What is static member?
3. What is static function?
4. What is static constructor?
5. How can we inherit a static variable?
6. How can we inherit a static member?
7. Can we use a static function with a non-static variable?
8. How can we access static variable?
9. Why main function is static?
10. How will you load dynamic assembly? How will create assesblies at run time?
11. What is Reflection?
12. If I have more than one version of one assemblies, then how will I use old version (how/where to specify version number?) in my application?
13. How do you create threading in.NET? What is the namespace for that?
14. What do you mean by Serialize and MarshalByRef?
15. What is the difference between Array and LinkedList?
16. What is Asynchronous call and how it can be implemented using delegates?
17. How to create events for a control? What is custom events? How to create it?
18. If you want to write your own dot net language, what steps you will you take care?
19. Describe the diffeerence between inline and code behind - which is best in a loosely coupled solution?
20. How dot net compiled code will become platform independent?
21. Without modifying source code if we compile again, will it be generated MSIL again?
22. How does you handle this COM components developed in other programming languages in.NET?
23. How CCW (Com Callable Wrapper) and RCW (Runtime Callable Wrappers) works?
24. What are the new thee features of COM+ services, which are not there in COM (MTS)?
25. What are the differences between COM architecture and.NET architecture?
26. Can we copy a COM dll to GAC folder?
27. What is Shared and Repeatable Inheritance?
28. Can you explain what inheritance is and an example of when you might use it?
29. How can you write a class to restrict that only one object of this class can be created (Singleton class)?
30. What are virtual destructures?
31. What is close method? How its different from Finalize and Dispose?
32. What is Boxing and UnBoxing?
33. What is check/uncheck?
34. What is the use of base keyword? Tell me a practical example for base keyword’s usage?
35. What are the different.NET tools which you used in projects?
36. What will do to avoid prior case?
37. What happens when you try to update data in a dataset in.NET while the record is already deleted in SQL Server as backend?
38. What is concurrency? How will you avoid concurrency when dealing with dataset?
39. One user deleted one row after that another user through his dataset was trying to update same row. What will happen? How will you avoid this problem?
40. How do you merge two datasets into the third dataset in a simple manner?
41. If you are executing these statements in commandObject. “Select * from Table1; Select * from Table2″ How you will deal result set?
42. How do you sort a dataset.
43. If a dataset contains 100 rows, how to fetch rows between 5 and 15 only?
44. What is the use of Parameter object?
45. How to generateXML from a dataset and vice versa?
46. How do you implement locking concept for dataset?
47. How will you do Redo and Undo in TextBox control?
48. How to implement DataGrid in.NET? How would you make a combo-box appear in one column of a DataGrid? What are the ways to show data grid inside a data grid for a master details type of tables? If we write any code for DataGrid methods. what is the access specifier used for that methods in the code behind file and why?
49. How can we create Tree control in asp.NET?
50. Write a program in C# to find the angle between the hours and minutes in a clock?
51. Write a program to create a user control with name and surname as data members and login as method and also the code to call it.
52. How can you read 3rd line from a text file?
53. Explain the code behind wors and contrast that using the inline style.
54. Explain different types of HTML, Web and server controls.
55. What are the differences between user control and server control?
56. How server form post-back works?
57. Can the action attribute of a server-side
tag be set to a value and if not how can you possibly pass data from a form page to a subsequent page?
58. How would ASP and ASP.NET apps run at the same time on the same server?
59. What are good ADO.NET object to replace to ADO Recordset object.
60. Explain the differences between Server-side code and Client-side code.
61. What type of code(server or client) is found in a Code-Behind class?
62. Should validation (did the user enter a real date) occur server-side or client-side? Why?
63. What does the “EnableViewState” property do? Why would I want it on or off?
64. What is the difference between Server.Transfer and response.Redirect? Why?
65. Can you give an example of when it would be appropriate to use a web service as opposed to a non-serviced.NET component?
66. Let’s say I have an existing application written using VB6 and this application utilizes Windows 2000 COM+ transaction services. How would you approach migrating this application to.NET?
67. If I am developing an application that must accomodate multiple security levels though secure login and my ASP.NET web application is spanned across three web-servers (using round-robin load balancing). What would be the best approach to maintain login-in state for the users?
68. What are ASP.NET web forms? How is this technology different than what is available though ASP(1.0-3.0)?
69. How does VB.NET achieve polymorphism?
70. How does C# achieve polymorphism?
71. Can you explain what is Inheritance and an example in VB.NET and C# of when you might use it?
72. Describe difference between inline and code-behind?
73. What is loosely coupled solution in.NET?
74. What is diffgram?
75. Where would you use an iHTTPModule and what are the limitations of any approach you might take in implementing one?
76. What are the Advantages and DisAdvantages of viewstate?
77. Describe session handling in a webform, how does it work and what are the limitations?
78. How would you get ASP.NET running in Apache web servers? Explain it’s limitations.
79. What is MSIL and why should my developers need an appreciation of it if at all?
80. Which methos do you invoke on the DataAdapter control to load your generated dataset with data?
81. Can you edit data in Repeater control? How?
82. Which template must you provide, in order to display data in a Repeater control?
83. How can you provide an alternating color scheme in a Repeater control?
84. What property must you set, and what method must you call in your code, in order to bind the data from some data source to the repeater control?
85. What base class do all web forms inherit from?
86. What method do you use to explicitly kill a user’s session? How?
87. How do you turn off cookies for one page in your site? Give an example.
88. Which two properties are on every validation control?
89. What tags do you need to add within the asp:datagrid tags to bind columns manually? Give an example.
90. How do you create a permanent cookie?
91. What tag do you use to add a hyperlink column to the dataGrid?
92. What is the standard you use to wrap up a call to a Web Service?
93. Which method do you use to redirect the user to another page without performing a round trip to the client? How?
94. What is the transport protocol you use to call a Seb Service SOAP?
95. What does WSDL stand for?
96. What property do you have to set to tell the grid which page to go to when using the Pager object?
97. Where on the Internet would you look for Web Services?
98. What tags do you need to add within the asp:datagrid tags to bind columns manually? How?
99. Which property on a Combo Box do you set with a column name, prior to setting the DataSource, to display data in the combo box?
100. How is a property designated as read-only?
101. Which control would you use if you needed to make sure the values in two different controls matched?
2. What is static member?
3. What is static function?
4. What is static constructor?
5. How can we inherit a static variable?
6. How can we inherit a static member?
7. Can we use a static function with a non-static variable?
8. How can we access static variable?
9. Why main function is static?
10. How will you load dynamic assembly? How will create assesblies at run time?
11. What is Reflection?
12. If I have more than one version of one assemblies, then how will I use old version (how/where to specify version number?) in my application?
13. How do you create threading in.NET? What is the namespace for that?
14. What do you mean by Serialize and MarshalByRef?
15. What is the difference between Array and LinkedList?
16. What is Asynchronous call and how it can be implemented using delegates?
17. How to create events for a control? What is custom events? How to create it?
18. If you want to write your own dot net language, what steps you will you take care?
19. Describe the diffeerence between inline and code behind - which is best in a loosely coupled solution?
20. How dot net compiled code will become platform independent?
21. Without modifying source code if we compile again, will it be generated MSIL again?
22. How does you handle this COM components developed in other programming languages in.NET?
23. How CCW (Com Callable Wrapper) and RCW (Runtime Callable Wrappers) works?
24. What are the new thee features of COM+ services, which are not there in COM (MTS)?
25. What are the differences between COM architecture and.NET architecture?
26. Can we copy a COM dll to GAC folder?
27. What is Shared and Repeatable Inheritance?
28. Can you explain what inheritance is and an example of when you might use it?
29. How can you write a class to restrict that only one object of this class can be created (Singleton class)?
30. What are virtual destructures?
31. What is close method? How its different from Finalize and Dispose?
32. What is Boxing and UnBoxing?
33. What is check/uncheck?
34. What is the use of base keyword? Tell me a practical example for base keyword’s usage?
35. What are the different.NET tools which you used in projects?
36. What will do to avoid prior case?
37. What happens when you try to update data in a dataset in.NET while the record is already deleted in SQL Server as backend?
38. What is concurrency? How will you avoid concurrency when dealing with dataset?
39. One user deleted one row after that another user through his dataset was trying to update same row. What will happen? How will you avoid this problem?
40. How do you merge two datasets into the third dataset in a simple manner?
41. If you are executing these statements in commandObject. “Select * from Table1; Select * from Table2″ How you will deal result set?
42. How do you sort a dataset.
43. If a dataset contains 100 rows, how to fetch rows between 5 and 15 only?
44. What is the use of Parameter object?
45. How to generateXML from a dataset and vice versa?
46. How do you implement locking concept for dataset?
47. How will you do Redo and Undo in TextBox control?
48. How to implement DataGrid in.NET? How would you make a combo-box appear in one column of a DataGrid? What are the ways to show data grid inside a data grid for a master details type of tables? If we write any code for DataGrid methods. what is the access specifier used for that methods in the code behind file and why?
49. How can we create Tree control in asp.NET?
50. Write a program in C# to find the angle between the hours and minutes in a clock?
51. Write a program to create a user control with name and surname as data members and login as method and also the code to call it.
52. How can you read 3rd line from a text file?
53. Explain the code behind wors and contrast that using the inline style.
54. Explain different types of HTML, Web and server controls.
55. What are the differences between user control and server control?
56. How server form post-back works?
57. Can the action attribute of a server-side
tag be set to a value and if not how can you possibly pass data from a form page to a subsequent page?
58. How would ASP and ASP.NET apps run at the same time on the same server?
59. What are good ADO.NET object to replace to ADO Recordset object.
60. Explain the differences between Server-side code and Client-side code.
61. What type of code(server or client) is found in a Code-Behind class?
62. Should validation (did the user enter a real date) occur server-side or client-side? Why?
63. What does the “EnableViewState” property do? Why would I want it on or off?
64. What is the difference between Server.Transfer and response.Redirect? Why?
65. Can you give an example of when it would be appropriate to use a web service as opposed to a non-serviced.NET component?
66. Let’s say I have an existing application written using VB6 and this application utilizes Windows 2000 COM+ transaction services. How would you approach migrating this application to.NET?
67. If I am developing an application that must accomodate multiple security levels though secure login and my ASP.NET web application is spanned across three web-servers (using round-robin load balancing). What would be the best approach to maintain login-in state for the users?
68. What are ASP.NET web forms? How is this technology different than what is available though ASP(1.0-3.0)?
69. How does VB.NET achieve polymorphism?
70. How does C# achieve polymorphism?
71. Can you explain what is Inheritance and an example in VB.NET and C# of when you might use it?
72. Describe difference between inline and code-behind?
73. What is loosely coupled solution in.NET?
74. What is diffgram?
75. Where would you use an iHTTPModule and what are the limitations of any approach you might take in implementing one?
76. What are the Advantages and DisAdvantages of viewstate?
77. Describe session handling in a webform, how does it work and what are the limitations?
78. How would you get ASP.NET running in Apache web servers? Explain it’s limitations.
79. What is MSIL and why should my developers need an appreciation of it if at all?
80. Which methos do you invoke on the DataAdapter control to load your generated dataset with data?
81. Can you edit data in Repeater control? How?
82. Which template must you provide, in order to display data in a Repeater control?
83. How can you provide an alternating color scheme in a Repeater control?
84. What property must you set, and what method must you call in your code, in order to bind the data from some data source to the repeater control?
85. What base class do all web forms inherit from?
86. What method do you use to explicitly kill a user’s session? How?
87. How do you turn off cookies for one page in your site? Give an example.
88. Which two properties are on every validation control?
89. What tags do you need to add within the asp:datagrid tags to bind columns manually? Give an example.
90. How do you create a permanent cookie?
91. What tag do you use to add a hyperlink column to the dataGrid?
92. What is the standard you use to wrap up a call to a Web Service?
93. Which method do you use to redirect the user to another page without performing a round trip to the client? How?
94. What is the transport protocol you use to call a Seb Service SOAP?
95. What does WSDL stand for?
96. What property do you have to set to tell the grid which page to go to when using the Pager object?
97. Where on the Internet would you look for Web Services?
98. What tags do you need to add within the asp:datagrid tags to bind columns manually? How?
99. Which property on a Combo Box do you set with a column name, prior to setting the DataSource, to display data in the combo box?
100. How is a property designated as read-only?
101. Which control would you use if you needed to make sure the values in two different controls matched?
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