partial void Deletehoadon(hoadon instance);
 partial void Updatehoadon(hoadon instance);
 private void detach_hoadons(hoadon entity)
 {
     this.SendPropertyChanging();
     entity.KhachHang = null;
 }
 partial void Inserthoadon(hoadon instance);
 private void attach_hoadons(hoadon entity)
 {
     this.SendPropertyChanging();
     entity.KhachHang = this;
 }