partial void DeleteDonDatHang(DonDatHang instance);
 partial void UpdateDonDatHang(DonDatHang instance);
 private void detach_DonDatHangs(DonDatHang entity)
 {
     this.SendPropertyChanging();
     entity.KhachHang = null;
 }
 partial void InsertDonDatHang(DonDatHang instance);
 private void attach_DonDatHangs(DonDatHang entity)
 {
     this.SendPropertyChanging();
     entity.KhachHang = this;
 }