ASP C# Gridview filtering from DropDownLis

Question

I want to fill my gridview1 with DropDownList1.

 

DropDownList1 is one column in one table, about 2000 hyperlink addresses in text or varchar whatever.

 

The GridView1 needs to show the actual hyperlink address in a real hyperlink format.  which will take 2 tables joined.  I am using a template within my gridview.

 

I have everything working except the DropDownList1 will not update the gridview based on selection.

 

I need to figure out how to do this part on the cs file.  Please help????????????