public void Insert_bill(Button bt, ListView lv, ComboBox cb, NumericUpDown nb, TextBox tx)
        {
            DAL_HOADON         hd  = new DAL_HOADON();
            DAL_THONGTINHOADON tt  = new DAL_THONGTINHOADON();
            BAL_BAN            ban = new BAL_BAN();

            BEL_BAN tb = lv.Tag as BEL_BAN;

            hd.Insert_Bill(tb.Soban);

            int idBill = hd.GetBill(tb.Soban);
            int idFood = (cb.SelectedItem as BEL_NUOC).Manuoc;
            int count  = (int)nb.Value;

            if (idBill == -1)
            {
                hd.Insert_Bill(idBill);
                tt.InsertBillInfo(hd.getMaxID(), idFood, count);
            }
            else
            {
                tt.InsertBillInfo(idBill, idFood, count);
            }

            ban.get_lv(lv, tx);
            ban.showBill(tb.Soban);
        }