private void barButtonItem2_ItemClick(object sender, ItemClickEventArgs e)
 {
     try
     {
         F696_Cham_cong_xls v_frm = new F696_Cham_cong_xls();
         if(IsExistFormName(v_frm)) return;
         v_frm.MdiParent = this;
         v_frm.Show();
     }
     catch(Exception v_e)
     {
         CSystemLog_301.ExceptionHandle(v_e);
     }
 }