private void btnAddDrink_Click(object sender, EventArgs e) { Table table = lsvDetailBill.Tag as Table; int idBill = BillDAO.GetBillByTable(table.ID); int idDrink = (cbDrink.SelectedItem as Drink).ID; int count = (int)nmCount.Value; if (idBill == -1) { BillDAO.InsertBill(table.ID); BillInfoDAO.InsertBillInFo(BillDAO.GetMaxBill(), idDrink, count); } else { BillInfoDAO.InsertBillInFo(idBill, idDrink, count); } ShowBill(table.ID); LoadTable(); }