how can i know which button is clicked

Hi,
This solution will be better for u for the problem... On which button has been clicked. For this u have to need override a method i.e. RaisePostBackEvent
which will tell u. i have tried it. try it.

protected override void RaisePostBackEvent(IPostBackEventHandler sourceControl, string eventArgument)
{
      string s = ((WebControl)sourceControl).ID;
      Response.Write(s.ToUpper());
}

Thanx & Regards

The whole idea is wrong. All the even-oriented UI are based not on checking up if the event has happened and what control is the sender, but rather on providing an appropriate event handler for a control.

Please see my comment to the question — it is not clear what should be detected. As I say, a sender does not have to be detected, and a key pressed is passed as an event parameter.

—SA