[RESOLVED] Textbox must contain 4 numbers

Ok, I've made a textbox which MUST contain 4 numbers. If there are 3 numbers (or less) you'll get an error or something. I already changed the tabindex to 4. Does someone know how to accomplish this?

You can use the Len function to check the length of the textbox.

Code:

---

        Dim what As String = TextBox1.Text
        If Len(what) < 4 Then
            MsgBox("no go")
        Else
            MsgBox("correct size")
        End If

---

Above code can be used after a buttonclick or TextBox1_TextChanged to check instantly.

Paul

You can also check if a number has been entered in the KeyPress event. If it is not a number set e.Handled to true (unless it is backspace chr(8)).

Thanks both for your help! Hakka's method worked for me though.