Limiting Textbox input

Is there a way to limit the input into a textbox to only alphanumeric character(just letters and numbers). I've seen a function that lets them only put in numbers, but not one for limiting it to letters and numbers

[Nitro]

You mean something like this:

Private Sub txtAlarm_KeyPress(KeyAscii As Integer)
'Prevents the user from pressing certain keys
'KeyAscii <> 8 means ==> 8 represent backspace
'(Key < "0" Or Key > "9") ==> only numbers are allow
'Only these characters are allow ==>
   '(Key <> ":") And (Key <> "a") And (Key <> "p") And (Key <> "m")
    
    
    
    Key = Chr$(KeyAscii)
    If KeyAscii <> 8 And _
      (Key < "0" Or Key > "9") And _
      (Key <> ":") And (Key <> "a") And (Key <> "p") And (Key <> "m") Then
        Beep
        KeyAscii = 0
    End If
End Sub

[Iain17]

This function will make sure that a key pressed is a number or a letter. You can also pass it a length value so that none of the length of the text can't go over a certain value. Pass length 0 for no limit.

To use this you pass the KeyAscii value, the length, and the textbox.

Private Sub Text1_KeyPress(KeyAscii As Integer)
    'infinite length
    KeyAscii = validateNormalKeyPress (Keyascii, 0, Text1)

    'length limited to 8
    KeyAscii = validateNormalKeyPress (Keyascii, 8, Text1)
End Sub


Function validateNormalKeyPress(KeyAscii As Integer, iLength As Integer, txtBox As TextBox) As Integer
    
    On Error GoTo validateKeyError
    
    If KeyAscii <> 8 Then
      
      'if the number of characters in the text box is
      'greater than iLength, and none of the charcters
      'are highlighted then set keyascii to 0
      If iLength <> 0 Then
        If (Len(txtBox.Text) >= iLength) And _
           (txtBox.SelLength = 0) _
        Then
          KeyAscii = 0
        End If
      End If
      
      'if the keypressed is not a number or a letter 
      'then set keyascii = 0
      
      If (KeyAscii <= 47) Or (KeyAscii >= 58) Then
        If (KeyAscii <= 64) Or (KeyAscii >= 91) Then
          If (KeyAscii <= 96) Or (KeyAscii >= 123) Then
            KeyAscii = 0
          End If
        End If
      End If
                        
    End If
    
    validateNormalKeyPress = KeyAscii
    
    Exit Function
    
validateKeyError:
    displayError "Error Validating Key Press :"

End Function

[Edited by Iain17 on 04-28-2000 at 10:14 AM]

[kedaman]

To prevent user from pasting nonalphanumeric chars from clipboard you should consider to put your code in the change event

[Iain17]

Cheers Kedaman.

I never though of that, i have been doing validation for a lot of text boxes, but i noticed the other day that the user could still paste what-ever crap they so wanted in the text box.

The user can never be trusted!

[SonGouki]

? Couldn't you also subclass the TextBox and toss out any WM_PASTE messages? Just an idea that I haven't got around to trying out yet.