ACC2000: Flexible Input Mask for Entering Five- or Nine-Digit ZIP Codes

Option Explicit
					

Function Zip (zipcode As Control)

  'Exit if a null is passed to the function.
  If IsNull(zipcode) Then
    Exit Function
  End If
  If IsThereAlpha(zipcode) Then
    Msgbox "Your ZIP Code Contains Letters"
    Exit Function
  Else
    'Strip unwanted characters, leaving only numbers.
    zipcode = ZStrip(zipcode, "-")
    zipcode = ZStrip(zipcode, " ")
    zipcode = ZStrip(zipcode, ")")
    zipcode = ZStrip(zipcode, "(")

    'Reformat the character string.
    Select Case Len(zipcode)
      Case 5
        Screen.ActiveControl = Format(zipcode, "@@@@@")
      Case 9
        Screen.ActiveControl = Format(zipcode, "@@@@@-@@@@")
      Case Else
        MsgBox "This is not a valid ZIP Code."
        Screen.ActiveControl = zipcode
    End Select
  End If
End Function

Function ZStrip (InZip, StripZip)
  Do While InStr(InZip, StripZip)
    InZip = Mid(InZip, 1, InStr(InZip, StripZip) - 1) & Mid _
    (InZip, InStr(InZip, StripZip) + 1)
  Loop
  ZStrip = InZip
End Function

Function IsThereAlpha (zipcode) As Integer
   Dim Pos, a_char$, Clean
   Pos = 1
   Clean = 0
   While (Pos <= Len(zipcode) And (Clean = 0))
      a_char$ = Mid(zipcode, Pos, 1)
      If a_char$ >= "0" And a_char$ <= "9" Then
         Clean = 0
      Else
         If a_char$ <> "-" Then Clean = 1
      End If
      Pos = Pos + 1
   Wend
   IsThereAlpha = Clean
End Function