Source code in C #

Hi,
  I have downloaded your executable file and when I parse any text its just showing me the same output with one rectangle box at last. What exactly you want in your code?

Regards,
Iftikar

hi,

Can you please provide more information on same?
do you want to copy data of one text box to other text box with processing data of first text box?

I don't know exactly what you mean by a tax code but if the user enters the gross income in one textbox and the tax rate (%) in another textbox, you can calculate and show the tax payable and net income in other textboxes as follows:

private void btnCalculate(object sender, EventArgs e)
{
   decimal grossIncome;
   bool isValid = decimal.TryParse(txtGrossIncome.Text, out grossIncome);
   if (!isValid || grossIncome < 0)
   {
      MessageBox.Show("Income is not a valid number. Please amend.");
      txtGrossIncome.Focus();
      return;
   }

   decimal taxRate;
   isValid = decimal.TryParse(txtTaxRate.Text, out taxRate);
   if (!isValid || taxrate < 0 || taxrate >= 100)
   {
      MessageBox.Show("TaxRate is not a valid number. Please amend.");
      txtTaxRate.Focus();
      return;
   }

   decimal taxPayable = Math.Round(grossIncome * taxRate / 100m);
   txtTaxPayable.Text = taxPayable.ToString();
   txtNetIncome.Text  = (grossIncome - taxPayable).ToString();
}