private void detach_BillDetals(BillDetal entity)
 {
     this.SendPropertyChanging();
     entity.Food = null;
 }
 partial void DeleteBillDetal(BillDetal instance);
 partial void InsertBillDetal(BillDetal instance);
 partial void UpdateBillDetal(BillDetal instance);
 private void attach_BillDetals(BillDetal entity)
 {
     this.SendPropertyChanging();
     entity.Bill = this;
 }