I'm trying to concatenate two table columns and have them display in a dropdown list, but the list shows as empty.  If I replace the "itemText" with "descr" below, then the dropdownlist gets filled.  It's not clear what I should have to the right of the SQL "AS" clause - itemText, @itemText, or [itemText] - but no matter what I put the SQL runs without error, but nothing displays in the list. 


In my dropdownlist datasource I have:

SelectCommand="SELECT [heading], [heading] + REPLICATE('.', 20 - LEN([heading])) + [descr] AS itemText FROM Testfile" 

For the sqldatasource I also Have:

    <SelectParameters>
      <asp:Parameter Name="itemText" Type="String" />
    </SelectParameters>

For the dropdownlist I have:
  <asp:DropDownList ID="DropDownList" runat="server" 
    DataSourceID="SqlDataSource" DataTextField="itemText" 
    DataValueField="ID_KEY" AutoPostBack="True" 
  </asp:DropDownList>