I have a nested dropdown inside a datagrid.  One for colors one for
sizes. Not all items have colors or sizes, however, so I need to find
a way to detect if the drop down is blank and make the control not
visible.  If there is a value then I need to add a choose a size. I am
having no problem with the choose a size being added to the control.
It just does not recognize when the value is null or blank. The
control is still visible.

  Dim myDataGridITem As DataGridItem

           For Each myDataGridITem In itemInfo.Items

               Dim ddlPsize As DropDownList
               ddlPsize = (myDataGridITem.FindControl("ddlsizes"))

               If ddlPsize.DataTextField Is GetType(DBNull) Then
                   ddlcolors.Visible = False

               Else

                   ddlPsize.Items.Insert(0, "Choose a Size")
               End If
                         Next