How to implement validation for negative values

Question

I was working on this code snippet

  private void calculateButton_Click(object sender, EventArgs e)
    {
        int amount;
        if (int.TryParse(amountText         


        

Answer 1

Store the value of TryParse result, then check the amount in the same if statement, like so:

boolean parseResult = int.TryParse(amountTextBox.Text, out amount)

if (parseResult && amount >= 0)
{
    //....
}
else
{
    MessageBox.Show("Invalid amount");
}