public void LoadUser(object sender, LoginEventArgs e)
        {
            _user = e.User;
            _user.LoadCardsLocal();
            FlierKey = _user.Cards[0][0];

            var gateway = new CardsGateway();
            var units   = gateway.GetUnits(_user.ID, Database.Instance);

            foreach (var item in units)
            {
                UnitsBox.Add(item);
            }
        }
        private void ClearButton_Click(object sender, EventArgs e)
        {
            DialogResult input = new Msg().Question("Confirm action?");

            if (input == DialogResult.Yes)
            {
                ClearButton.Text = "Clear";
                PriceLabel.Text  = "Total";

                OrderList.Rows.Clear();
                UnitsBox.Clear();
                TotalPriceBox.Clear();

                PayButton.Enabled      = true;
                AddItem.Enabled        = true;
                QuantityButton.Enabled = true;
            }
        }