CODEWITHSUNDEEP
c#validation
Robert Paulson
Robert Paulson

Reputation: 33

How to implement validation for negative values

I was working on this code snippet

  private void calculateButton_Click(object sender, EventArgs e)
    {
        int amount;
        if (int.TryParse(amountTextBox.Text, out amount))
        {
            wantedTextBox.Text = Currency_Exchange.exchangeCurrency((Currencies)currencyComboBox.SelectedIndex, (Currencies)wantedCurrencyComboBox.SelectedIndex, amount).ToString("0.00");                
            wantedCurrencyLable.Text = ((Currencies)wantedCurrencyComboBox.SelectedIndex).ToString();
        }

        else {
            MessageBox.Show("Invalid amount");
        }


    }

and realized way too late that I should put in validation for negative numbers. But the way i've set up the code makes that slightly difficult. How could I do this?

Upvotes: 0

Views: 888

Answers (1)

user2209008
user2209008

Reputation:

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");
}

Upvotes: 2

Related Questions