vb.net - Best way to limit textbox decimal input in c#

Question

How can I make a textbox in which can be only typed a number like 12.00 or 1231231.00 or 123123

I've done this in a very long way and I'm looking for the best and fastest way.

Also the decimal separator must be culture specific.:

Application.CurrentCulture.NumberFormat.NumberDecimalSeparator

Answer 1

The Validating event was made to do that. Drop an ErrorProvider control on your form so you can subtly remind the user that she did something wrong. The event also allows you to format the text box text the way that make sense. Like this:

    private void textBox1_Validating(object sender, CancelEventArgs e) {
        // Empty strings okay?  Up to you.
        if (textBox1.Text.Length > 0) {
            decimal value;
            if (decimal.TryParse(textBox1.Text, out value)) {
                textBox1.Text = value.ToString("N2");
                errorProvider1.SetError(textBox1, "");
            }
            else {
                e.Cancel = true;
                textBox1.SelectAll();
                errorProvider1.SetError(textBox1, "Please enter a number");
            }
        }
    }