private void btnConfirm_Click(object sender, EventArgs e)
        {
            string Username = frmLogin.loggedUser;

            if (dgvSell.RowCount > 0)
            {
                int rowcount = dgvSell.RowCount;
                sale.addBills(Username, txtBillName.Text.ToUpper(), DateTime.Now);
                int BillID = Convert.ToInt32((from p in sale.bills
                                              orderby p.billID descending
                                              select p.billID).First());
                for (int i = 0; i < rowcount; i++)
                {
                    int    Price    = Convert.ToInt32(dgvSell.Rows[i].Cells[2].Value.ToString());
                    string FoodName = dgvSell.Rows[i].Cells[0].Value.ToString();
                    int    Amount   = Convert.ToInt32(dgvSell.Rows[i].Cells[1].Value.ToString());
                    int    Total    = Price * Amount;
                    int    FoodID   = Convert.ToInt32((from p in sale.foods
                                                       where p.foodName == FoodName
                                                       select p.foodID).First().ToString());
                    sale.addBillInfo(FoodID, BillID, Amount, Total);
                }
                sale.updateBills(BillID, Convert.ToInt32(txtTotal.Text));
                if (cbTable.Text != "0")
                {
                    sale.updateCoffeeTable(Convert.ToInt32(cbTable.Text), BillID, "full");
                }
                frmBillInfo frm = new frmBillInfo(BillID.ToString());
                frm.ShowDialog();
            }
            btnClear_Click(sender, e);
        }
        private void ptbView_Click(object sender, EventArgs e)
        {
            string BillID = (from p in table.coffeeTables
                             where p.tableID == Convert.ToInt32(lblTN.Text)
                             select p.billID).First().ToString();
            frmBillInfo fr = new frmBillInfo(BillID);

            fr.ShowDialog();
        }
        private void ptbInfo_Click(object sender, EventArgs e)
        {
            frmBillInfo frm = new frmBillInfo(dgvBill.SelectedCells[0].OwningRow.Cells[0].Value.ToString());

            frm.ShowDialog();
        }