VBA Validate textbox value to have alphanumeric characters

Hi all!

Please assist me in solving this problem.
I just want the textbox to check upon exit event if the value entered is alphanumeric.
I have a code that checks every keypress if user enters non-alphanumeric characters. But again, I also want it to make sure that user entered alphanumeric characters coz this textbox is for user password.

Thanks!

Here's my code:

Private Sub Textbox2_KeyPress (ByVal KeyAscii As MSForms.ReturnInteger)
If Textbox2.Name <> "textbox2" Then
Select Case KeyAscii
Case 46, 48 to 57, 65 to 122
Case Else
KeyAscii = 0
Msgbox "Please enter alphanumeric characters only."
End Select
End If

Would something like this help you out?

Private Sub TextBox1_Exit(ByVal Cancel As MSForms.ReturnBoolean)
    Dim txtVal As String
    Dim txtLength As Integer
    Dim val As String
    
    txtVal = TextBox1.Value
    txtLength = Len(txtVal)
    
    For i = 1 To txtLength
        val = Mid(txtVal, i, 1)
        Select Case Asc(UCase(val))
            Case 48 To 57, 65 To 90
            Case Else
                MsgBox "NO GOOD BRO!"
                Cancel = True
                TextBox1.SetFocus
                TextBox1.SelStart = 0
                TextBox1.SelLength = txtLength
                Exit Sub
        End Select
    Next i
End Sub

Hi BigBas!
Thanks for replying
I tried your code but the textbox accepts all type of entries upon exit, may it be letters only, numbers only, or aplhanumeric.

Any more insight?
Thanks!

Any more insight?
Thanks!

Perhaps I misunderstood your request. You are correct, the code allows letters, numbers, or both. Are you asking to REQUIRE that the user enter at least one letter and one number?

Originally Posted by BigBas

Perhaps I misunderstood your request. You are correct, the code allows letters, numbers, or both. Are you asking to REQUIRE that the user enter at least one letter and one number?

Yes, BigBas! I'm sorry if I confused you. This textbox is where user needs to enter their new password. And I believe, for better security, it's better for a password to be alphanumeric, right?

Thanks again in advance!

That sounds right. Earlier, I though you were trying to block the user from entering NON alpha-numeric data (special characters such as: ! @ # $ etc).

The below code requires at least 1 letter and 1 number. You can further strengthen the password by requiring a minimum length, or any other requirements.

Private Sub TextBox1_Exit(ByVal Cancel As MSForms.ReturnBoolean)
    Dim txtVal As String
    Dim txtLength As Integer
    Dim val As String
    Dim nums As Integer
    Dim letters As Integer
    
    txtVal = TextBox1.Value
    txtLength = Len(txtVal)
    
    nums = 0
    letters = 0
    For i = 1 To txtLength
        val = Mid(txtVal, i, 1)
        Select Case Asc(UCase(val))
            Case 48 To 57
                nums = nums + 1
            Case 65 To 90
                letters = letters + 1
            Case Else
        End Select
    Next i
    
    If letters = 0 Or nums = 0 Then
        MsgBox "NO GOOD BRO!"
        Cancel = True
        TextBox1.SetFocus
        TextBox1.SelStart = 0
        TextBox1.SelLength = txtLength
    End If
End Sub

Thank you so much, BigBas!!!
That worked perfectly! Also, I limit the password length to 10 characters only, as you recommended.

Hi MarvinP,
I'll also look into your link to find more insights. For now, I'm tagging this post as SOLVED!

Thanks for this forum as always!

Glad to help!