By default, buttons and other controls in ASP.NET pages post back to the same page that contains the control. Many times during web site development developers need to send user to a different page. We can use Server.Transfer method to move user between pages, however by using this technique the URL doesn’t change.
ASP.NET 2.0 introduced new feature that allows you to post back from one page to another, and you can obtain the values of first page controls in the target page. This feature is very useful for multi page form scenario where you want to collect different information on each page. To configure controls to get benefit of the cross page posting the control should have IButtonControl interface implemented. In .NET Framework Button, ImageButton and LinkButton all three implements the IButtonControl interface.