How to make sure that despite using validation control on your.aspx page, your page is valid? or how to validate the page in the server side?

use Page.IsValid method, this revalidate your data server side against each Validation control used.
Read more http://www.dotnetfunda.com/interview/exam114_how_to_make_sure_that_despite_using_validation_control_on_youraspx_pa.aspx
Author: Raja

What is the location of Global Assembly Cache on the system.

C:\$WINDOWS\assembly
Read more http://www.dotnetfunda.com/interview/exam119_what_is_the_location_of_global_assembly_cache_on_the_system.aspx
Author: Raja

What is the use of CommandBehavior.CloseConnection?

We can use pass it with ExecuteReader method of Command object like
reader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
This will make sure that when we are calling reader.Close() the associated connection object will also be closed.
Read more http://www.dotnetfunda.com/interview/exam112_what_is_the_use_of_commandbehaviorcloseconnection.aspx
Author: Raja

What is DOM?

Document Object Model (DOM) is a W3C specification that defines a standard (abstract) programming API to build, navigate and update XML documents. It is a "tree-structure-based" interface. As per the DOM specification, the XML parsers (such as MSXML or Xerces), load the entire XML document into memory, before it can be processed. XPath is used [...]

How to declare a property in a class?

int m_PersonID = 0;
public int PersonID { get { return m_PersonID; } set { m_PersonID = value; } }
Read more http://www.dotnetfunda.com/interview/exam120_how_to_declare_a_property_in_a_class.aspx
Author: SheoNarayan

What’s the difference between private and shared assembly?

[B]Private Assembly[/B] is used inside an application only and does not have to be identified by a strong name.
[B]Shared Assembly [/B] can be used by multiple applications and has to have a strong name.
Read more http://www.dotnetfunda.com/interview/exam118_whats_the_difference_between_private_and_shared_assembly.aspx
Author: Raja

What is typed dataset ?

A typed dataset is very much similar to a normal dataset. But the only difference is that the sehema is already present for the same. Hence any mismatch in the column will generate compile time errors rather than runtime error as in the case of normal dataset. Also accessing the column value is much easier [...]

Can you place two .dll files with the same name in GAC (Global Assembly Cache)?

Yes, provided both have different versions.
GAC is a Folder that contains .dll that have strong name. So we can keep myproject.dll and myproject.dll two files into GAC with different version like 1.0.0.0 and 1.0.0.1
Read more http://www.dotnetfunda.com/interview/exam117_can_you_place_two_dll_files_with_the_same_name_in_gac_global_assembl.aspx
Author: Raja

How to declare a property in an Interface?

DateTime DateOfBirth { get;set;} int Age { get;set;} string FirstName { get;set;}
As this is an Interface, so no implementation required only definition of properties are required. Implementation of these properties will be written into the class inherting this interface.
Read more http://www.dotnetfunda.com/interview/exam121_how_to_declare_a_property_in_an_interface.aspx
Author: SheoNarayan

Can you edit data in Repeater control?

No, it is readonly and forward only control so we can’t edit data in repeater control.
Read more http://www.dotnetfunda.com/interview/exam116_can_you_edit_data_in_repeater_control.aspx
Author: Raja