private void listBox_lv1_SelectedIndexChanged(object sender, EventArgs e)
 {
     if (listBox_lv1.SelectedIndex != -1)
     {
         consMgr.setAPLv2(listBox_lv2, int.Parse(((PermissibleValueObj)(listBox_lv1.SelectedItem)).Value));
         if (listBox_lv2.Items.Count == 1)
         {
             listBox_lv2.SelectedIndex = 0;
         }
     }
 }