protected void SendButton_Click(object sender, EventArgs e)
        {
            if (Page.IsValid)
            {
                Receipt receipt = new Receipt(new double());
                receipt.Calculate(double.Parse(InputBox.Text));

                Total.Text = String.Format("{0:c}",receipt.Subtotal);
                Rabattsats.Text = String.Format("{0}%",receipt.DiscountRate);
                Rabatt.Text = String.Format("{0:c}", receipt.MoneyOff);
                Pay.Text = String.Format("{0:c}", receipt.Total);
                Kvitto.Visible = true;
            }
        }
 protected void CalcDiscount_Click(object sender, EventArgs e)
 {
     if (IsValid)
     {
         double theSum;
         if (double.TryParse(InputField.Text, out theSum)) // lika bra att va extra säker med tryparse
         {
             Receipt rec = new Receipt(theSum);
             rec.Calculate(theSum);
             DrawReceipt(rec);
         }
         else
         {
             ErrorText.Text = "Error! Något blev fel vid parsningen";
         }
     }
 }