I noticed this post at vbCity and after looking at the code wondered if I could come up with a more compact solution and I think I have.
Private Function FindNumberOfUniqueCharactersInString(ByVal strVvText As String _
, ByVal blnVvCaseSensitive As Boolean _
) As Integer
Dim intLvIndex As Integer
Dim intLvCount As Integer: intLvCount = 1
strVvText = IIf(blnVvCaseSensitive, strVvText, UCase$(strVvText))
For intLvIndex = 2 To Len(strVvText)
If InStr(Left(strVvText, intLvIndex - 1) _
, Mid(strVvText, intLvIndex, 1) _
) = 0 Then
intLvCount = intLvCount + 1
End If
Next
FindNumberOfUniqueCharactersInString = intLvCount
End Function
There are possibly even more compact and elegant solutions to this interesting little issue but I quite like my solution :)