Given a pulldown template like:

     <asp:TemplateColumn HeaderText="PO Line">
     <ItemTemplate>
      <asp:Label id="TX_POLine" runat="server" BorderColor="#E0E0E0"
BackColor="White" BorderStyle="Solid"></asp:Label>
     </ItemTemplate>
     <EditItemTemplate>
      <asp:DropDownList id="CB_POLine" runat="server"
Width="75px"></asp:DropDownList>
     </EditItemTemplate>
    </asp:TemplateColumn>

How/where can I populate the pulldown in code?

I've tried everything I can think of to find that pulldown, but with no
luck. My latest attempt was:
For liRow = 0 To DG_List.Items.Count - 1
pd = CType(DG_List.Items(lirow).FindControl("CB_POLine"), DropDownList)
If Not pd Is Nothing Then
 ' --- should break here if the pulldown is found
End If
Next

Thanks