You can store the selected item text into session state and read it from there.
But first add the OnSelectedItemChanged event to your dropdownlist and set AutoPostBack=true.
This link solves your problem: http://forums.asp.net/post/5162366.aspx
Edit:
In case the user didn't change the dropdownlist value, you'll need to modify the UploadComplete method to the following:
protected void UploadComplete(object sender, AjaxControlToolkit.AjaxFileUploadEventArgs e)
{
String value;
if(Session["Value"] != null)
{
value = Session["Value"].ToString();
}
else
{
value = DropDownList1.SelectedItem.Text;
}
//rest of your code
}
And you can set the default selected listitem in dropdownlist like this:
<asp:DropDownList ID="DropDownList1" runat="server" Font-Size="Smaller">
<asp:ListItem Selected="True" >CEESI</asp:ListItem>
<asp:ListItem>NEL</asp:ListItem>
<asp:ListItem>HORSOY</asp:ListItem>
<asp:ListItem>FLATOY</asp:ListItem>
<asp:ListItem>CEPRO</asp:ListItem>
<asp:ListItem>SINTEF</asp:ListItem>
</asp:DropDownList>