how to process postbacks

There are tow issues in handling  Post Back:How to handle Post Back Data,and how to Handle Post Back Events.

A control that needs to examine form data that is posted back to the server must implement the IPostBackData Handler interface.

A control that needs to handle post back events must implement the IPostBackEventhandler interface.

The IPostBackData interface enables the control to access data accompnaying a post back event and to update its properties accordingly.

The interface defines two methods which must be implemented in a class that derives form it:
LoadPostData,which the .NET calls to pass postback data to the control
RaisePostDataChangedEvent,which is called after LoadPostData,to give the control the opportunity to fire events resulting from changes in its interal state following a postback.

Custom Controls that capture form submit information from the browser must implement the IPostBackEventHandler interface.

the contract of the interface allows a control to raise events on the server in response to post back form the client.

the IPostBackEventHandler interface contains one method,RaisePostBackEvent