GridView being bound using more than one parameter from other controls

I know that the GridView can be populated with parameter values from other controls.  i.e I have written stuff so that if an item was selected from a DropDownList, the GridView was rebound using that parameter.  I now have a search form but I don't want the GridView to be rebound until the user clicks the Search button and there will be parameters from 3 DropDownLists.  How do I do this without using code behind?  At the moment I'm doing it from codebehind but the paging is not working when I bind from the code behind - this is why I'm looking for a different solution.  I'm using .Net 4.