This post will explain two different ways to bind a GridView (or DetailsView, or any other NamingContainer) to its EntityDataSource when your filtering/search controls are in the header row. This method can be used to break out of pretty much any NamingContainer and assign values to a control that’s on the form (same level as your dataSource).

This post will show you how to use the AJAX Control Toolkit’s AutoCompleteExtender and a very simple javascript call to save a key/value to an asp.net hidden field.