override void OnPreRender (EventArgs e)
{
base.OnPreRender (e);
// Register all of the checked controls so we can
// find out when they are unchecked.
for (int i = 0; i < Items.Count; i++) {
if (Items [i].Selected) {
check_box.ID = i.ToString (Helpers.InvariantCulture);
Page.RegisterRequiresPostBack (check_box);
}
}
}