Redirect to specific index in Dropdownlist

Question

I have a page that contains a drop down list populated with report names of rdl files.  This is not an items list, it is dynamically created with the report names that a certain user is able to access after authentication.  What I need to do is redirect from one page to a particular item from the ddl.  I have tried setting a Session variable & checking for that when reloading the reports page, but it will not load the report I want.  here is the code on the reports page:
if(Session["session"] != null) {
for (int i = 0; i < ddl.Item.Count; i++) {
if(ddl.Items[i].Value == "12") {
ddl.SelectedIndex = i;
break;
}
any suggestions are helpful.
thanks
Bonnie