public int Xoa(DANGKYHOATDONG lpDTO)
 {
     try
     {
         LinQDataContext db = new LinQDataContext(global::DAOAuction.Properties.Settings.Default.webdoantruongConnectionString);
         db.DANGKYHOATDONG_delete(
             lpDTO.MaNguoiDung,
             lpDTO.MaHoatDong
             );
         db.SubmitChanges();
         return 0;
     }
     catch (Exception ex)
     {
         throw (ex);
     }
 }