Weird problem with dropdownlist and SelectedValue

I'm kinda scratching my head at this one.  I bind a dropdownlist to a list of files in a directory, which is fine.  But then when I try to get the SelectedValue, it always returns the first item.  Anyone know why?

Imports System
Imports System.IO
 
Partial Class ReplaceInherits System.Web.UI.Page
 

Protected Sub Page_Load(ByVal sender < ...