private void DisplayLevel2List() { if (string.IsNullOrEmpty(Level2Original())) { // display an empty list cboLevel2Manual.DataSource = null; } else { // display lists based on selected level 1 var level1 = SelectedValue(cboLevel1Manual); if (level1 == null) { // display an empty list cboLevel2Manual.DataSource = null; } else { var list = geoCoder.Level2GazetteerNames( SelectedValue(cboLevel1Manual)); // format - add a leave blank option to the bottom of the list list.Add(LeaveBlankText); cboLevel2Manual.DataSource = list; } } }