Master Details using AJAX and the UpdatePanelPopupExtender
This is old code. Consider using these methods instead:
Ajax control toolkit Modal Popup
The UpdatePanelPopupExtender is a simple ASP.Net AJAX extender that can be attached to any UpdatePanel control. This extender allows you to postion the attached UpdatePanel beside any control you specify. Here are a couple screen shots of what you can do with it.
This shows an UpdatePanel positioned next to a "Details Icon". The UpdatePanel contains a DetailsView which displays details of the record selected. This allows for editing of the current row in the GridView.
Master Multiple Details
Uses the Wizard control as a sidebar navigator
The results are returned in a multiple column GridView with the GridView paging turned on.
Download Code and sample here (look under Flan AJAX Controls)
Please let me know what you think. Thanks.