Question

How do I prevent a textbox value from changing after a certain keypress? For example, I’m trying to prevent numbers from being input, if a number is input a message box is displayed however the number is still being printed. How can I get it so the number is not printed?

private void textBox_KeyPress(object sender, KeyPressEventArgs e)
{
    if (e.KeyChar == '1')
    {
        MessageBox.Show("Only letters please");
    }
}

Thanks in advance,
Ari

Answer 1

private void textBox1_TextChanged(object sender, EventArgs e)
{
    if (Regex.IsMatch(textBox1.Text, "[0-9]"))
    {
        MessageBox.Show("Only letters please");
        textBox1.Text = Regex.Replace(textBox1.Text, "[0-9]", String.Empty);
    }
}