Textbox for price/cash/currency on C#

Question

I have a problem that is haunting me for a while. I tried some solutions but they didn\'t worked.

I have a textbox that is for cash input ($999,99 for example). Howe

Answer 1

Just a slight modification to GreatNates answer.

private bool KeyEnteredIsValid(string key)
{
  Regex regex;
  regex = new Regex("[^0-9]+$"); //regex that matches disallowed text
  return regex.IsMatch(key);
}

and insert this method into the textboxs preview input event like this.

private void TextBox1_PreviewTextInput(object sender, TextCompositionEventArgs e)
{
  e.Handled = KeyEnteredIsValid(e.Text);
}

That way you make sure that you can't make any mistakes when typing anything. You are limited to numbers only with my methods, while nates methods are formatting your string.

Cheers.