I would like to have a validation on my text box based the users input (keypress event). I have set the max length of my text box to 3 characters. The first character entered by the user should be a character (from a-z) and then the two succeeding characters must be a number. Backspace is allowed. So far I have this code but does not work as I would want to..
private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
countChar = this.textBox1.Text;
if (String.IsNullOrEmpty(this.textBox1.Text))
{
e.Handled = !(char.IsLetter(e.KeyChar) || e.KeyChar == (char)Keys.Back);
}
else if (countChar.Length == 1)
{
e.Handled = e.KeyChar == (char)Keys.Back;
}
else if (countChar.Length == 2 || countChar.Length == 3)
{
e.Handled = e.KeyChar >= '0' && e.KeyChar <= '9' || e.KeyChar == (char)8;
}
}
Any suggestions?
This should work
private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
countChar = this.textBox1.Text;
if (String.IsNullOrEmpty(this.textBox1.Text))
{
e.Handled = !(char.IsLetter(e.KeyChar) || e.KeyChar == (char)Keys.Back);
}
else if (countChar.Length == 1 || countChar.Length == 2)
{
e.Handled = !(char.IsDigit(e.KeyChar) || e.KeyChar == (char)Keys.Back);
}
else if (countChar.Length == 3)
{
e.Handled = e.KeyChar != (char)Keys.Back;
}
else
{
e.Handled = true;
}
}