The IsAlphanumeric Function

Public Function IsAlphanumeric(intKeyAscii As Integer, _
    Optional blnEscTabBackReturn = True) _
    As Boolean

    'Copyright (c) Brendan Reynolds/Timarco Ltd, 1999.
    'All rights reserved.
    
    'e-mail [email protected]
    
    'This function returns True if the intKeyAscii argument
    'is the ASCII code for an alphanumeric key ('a' to 'z',
    'upper or lower case, or '0' to '9'). By default, the
    'function will also return True if intKeyAscii is the
    'ASCII code for the Escape, Tab, Backspace or Return
    'key. This behaviour can be over-ridden by passing a
    'value of False for the optional argument
    'blnEscTabBackReturn.
    
    'Use (from the KeyPress event of a control or form):
    
    'blnAlphaNum = IsNumeric(KeyAscii)
    
    'Alternatively:
    
    'If IsNumeric(KeyAscii, False) Then
    '   do something
    'Else
    '   do something else
    'End If
    
On Error GoTo Err_Routine
    
    Dim lngErrNum As Long
    
    Select Case intKeyAscii
    Case Asc("A") To Asc("Z")
        IsAlphanumeric = True
    Case Asc("a") To Asc("z")
        IsAlphanumeric = True
    Case Asc("0") To Asc("9")
        IsAlphanumeric = True
    Case vbKeyEscape, vbKeyTab, vbKeyBack, vbKeyReturn
        If blnEscTabBackReturn Then
            IsAlphanumeric = True
        Else
            IsAlphanumeric = False
        End If
    Case Else
        IsAlphanumeric = False
    End Select
    
Exit_Routine:
    Exit Function
    
Err_Routine:
    lngErrNum = Err.Number
    Select Case Err
        '
    Case Else
        Err.Raise lngErrNum
        Resume Exit_Routine
    End Select

End Function

Download this function in plain text format, ready for import into your own Microsoft Access 97 or Microsoft Access 2000 application, here.

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