Asc

Public Function Asc(ByVal InputString As String) As Long

Returns the ANSI character code of the (first character) of the specified string (0-255).

Public Function ValidateString(pInputString) As Boolean
   Dim lCount As Long
   
   For lCount = 1 To Len(pInputString)
       If Asc(Mid(pInputString, lCount)) < 32 Then Return False 'Invalid character
   Next
   
   Return True
End Function

See also: