Forgive me I am new to this.

But I would like to use the ModalPopupExtender as a search popup window. What I mean is that I would like for my users to click on a button on the original page and up pops a Panel (With use of the ModalPopupExtender). Inside the popup panel there is a text box a button and a gridview. The user types what they are searching for in the text box and then clicks on the button that is inside the popup panel to start the search. The results need to show in the gridview that is inside the popup panel. Then the user would click on thier choice inside the gridview and what they clicked on would now appear in another text box that is on the page behind the popup panel.

Like I said I am trying to use the ModalPopupExtender. The problem is that when I click on the button to start the search the popup goes away. I am sure it has something to do with when I click on the search button it causes a postback. But I have to do a post back to get the results in the gridview.

Please help Very frustrated.

Thanks

In the button handler, simply call YourModalPopupExtenderId.Show(); at the very end.

I suppose your search procedure should be run in the server-side.
Just put the content of your popup (with grid, textbox and search button) into UpdatePanel for partial postback.