1. What should you do to store an object in a Viewstate?

Do serialization of convert the object to string

2. What should one do to make class serializable?

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;
}

3. What is Viewstate in .NET?

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.

4. What is the use of ErrorProvider Control in .NET?

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.

5. What is the Difference 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));
}

6. Which DLL translate XML to SQL in Internet Information Server (IIS)?

Sqlisapi.dll
DLL used to translate XML to SQL in Internet Information Server (IIS)

7. 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

8. 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 run time 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.

9. 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


http://msdn.microsoft.com/library/default.asp?url=/library/ en-us/vbcon/html/vbconwebusercontrolsvscustomwebcontrols.asp

10. Which dll is required to translate XML to SQL in Internet Information Server (IIS)?

Microsoft.data.sqlxml.dll used to translate XML to SQL using Internet Information Server IIS

Download Interview PDF

11. 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 Behavior is controlled by the connection string parameters.
Following the the 4 parameters that control most of the connection pooling behavior.
1. Connect Timeout
2. Max Pool Size
3. Min Pool Size
4. Pooling
Please go through the following link as well
http://support.microsoft.com/default.aspx?scid=kb;EN-US;q169470

12. 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 receives 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)

13. What 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.

14. 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.

15. 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”)

16. 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

17. ASP.NET interview questions list only?

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?

18. What is the base class of Button control in .NET?

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

19. What is the base class of .NET?

Base class provides a base set of methods that all derived classes can use

20. Main differences between ASP and ASP.NET?

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

21. 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++

22. .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

23. 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.

25. What is CLR in .NET?

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.

26. What is an interface and what is an abstract class? Please, expand by examples of using both. Explain why?

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).

27. List of ASP.NET interview questions only?

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?

28. 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 start up. If you're going to depend on it for storing session state, you'll want to change that to automatic start up 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.

29. 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.

30. How many types of exception handlers are there in .NET?

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.

31. Explain Difference between Panel and GroupBox classes using .NET?

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

32. Explain DataSet.AcceptChanges and DataAdapter.Update methods in .NET?

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.

33. Explain assemblies in .NET?

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.

34. Explain how Viewstate is being formed and how it's stored on client in .NET?

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.)

35. 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.