private void calculateButton_Click(object sender, EventArgs e)
{
var inputModel = new TaxInputModel
{
MonthlySalary = salaryUpDown.Value,
NrOfChildren = (int)childrenUpDown.Value
};
var calculator = new TaxCalculator();
var result = calculator.Calculate(inputModel);
var resultBuilder = new StringBuilder();
resultBuilder.AppendFormat("Net salary: {0} Ft", result.NetSalary);
resultBuilder.AppendLine();
resultBuilder.AppendFormat("Total cost: {0} Ft", result.TotalCost);
resultBuilder.AppendLine();
resultTextBox.Text = resultBuilder.ToString();
}