protected void ReceiptButton_Click(object sender, EventArgs e)
        {
            if (IsValid) {

                try
                {
                    Model.Reciept rec = new Model.Reciept();

                    rec.Calculate(int.Parse(SumTextBox.Text));

                    RecieptPanel.Visible = true;

                    SubLiteral.Text = String.Format(SubLiteral.Text, rec.Subtotal);

                    DiscountLiteral.Text = String.Format(DiscountLiteral.Text, rec.DiscountRate);

                    MoneyOffLiteral.Text = String.Format(MoneyOffLiteral.Text, rec.MoneyOff);

                    MoneyDueLiteral.Text = String.Format(MoneyDueLiteral.Text, rec.Total);

                }
                catch (Exception)
                {

                    throw;
                }
            }
        }
        protected void SubmitButton_Click(object sender, EventArgs e)
        {
            if (IsValid)
            {
                Reciept r = new Reciept(double.Parse(MainTextBox.Text));

                TotalLabel.Text = String.Format("{0:c}",r.Subtotal);
                RabattsattsLabel.Text = String.Format("{0:p0}", r.DiscountRate);
                RabattLabel.Text = String.Format("{0:c}", r.MoneyOff);
                AttBetalaLabel.Text = String.Format("{0:c}", r.Total);
                recieptbox.Visible = true;
            }
        }