partial void BtnCalculate_TouchUpInside(UIButton sender)
        {
            int amount = 0;

            Int32.TryParse(txtAmount.Text, out amount);
            double result = TaxFinder.CalculateTax(amount);

            lblResult.Text = result.ToString();
        }
        public void OnBtnCalculateClick(View v)
        {
            EditText txtAmount = (EditText)FindViewById(Resource.Id.txtAmount);
            TextView lblResult = (TextView)FindViewById(Resource.Id.lblResult);

            int amount = 0;

            Int32.TryParse(txtAmount.Text, out amount);

            double result = TaxFinder.CalculateTax(amount);

            lblResult.Text = result.ToString();
        }