public IEnumerable<NGUYEN_VONG_SearchResult> NGUYEN_VONG_Search(NGUYEN_VONG_SearchResult data, int? top)
 {
     try
     {
         using (var db = new OOAD_EDUManagementDataContext())
         {
             return db.NGUYEN_VONG_Search(data.maNguyenVong,
                                           data.maXNguyenVong,
                                           data.tenNguyenVong,
                                           data.doUuTien,
                                           data.maNguoiLap,
                                           data.thoiGianLap == null ? "" : data.thoiGianLap.Value.ToString(Constants.FormatDate),
                                           data.maNguoiDuyet,
                                           data.thoiGianDuyet == null ? "" : data.thoiGianDuyet.Value.ToString(Constants.FormatDate),
                                           data.maTrangThaiDuyet,
                                           data.trangThaiDuLieu,
                                           top).ToList();
         }
     }
     catch (Exception e) { return null; }
 }