Printing POSTNET barcodes in Visual Basic

' POSTools v6.0 Copyright 2008 Jerry Whiting. All rights reserved.
' Azalea Software, Inc. www.azalea.com
Dim yourString as String
If Not IsNumeric(yourSring) Then
  ' error handling
End If

If Len(yourString) <> 5 And Len(yourString) <> 10 And Len(yourString) <> 13 Then
  ' the ZIP code input must be 5-, 9- or 11-digits
  Exit Sub
End If
' strip the hyphen and space if need be. "12345-6789" to "123456789" or "12345-6789 00" to "12345678900"
Select Case Len(yourString)
  Case 13
    yourString = Left$(theZIP, 5) & Mid$(theZIP, 7, 4) & Right$(theZIP, 2)
  Case 10
    yourString = Left$(theZIP, 5) & Right$(theZIP, 4)
End Select

To do a POSTNET bar code:

Function AzaleaPOSTNET(ByVal theZIP as String) as String
' POSTools v6.0 Copyright 2008 Jerry Whiting. All rights reserved.
' Azalea Software, Inc. www.azalea.com

  ' The input, theZip, is a string for the ZIP code.
  ' The input should be all numbers, no hyphens or spaces. "12345", "123456789", or "12345678900"
  ' Format the output, AzaleaPOSTNET, using Azalea's POSTNET font.
  Dim theZIP As String
  Dim i As Integer ' loop counter
  Dim checkDigit As Integer ' check digit variable
  ' set up variable
  checkDigit = 0
  ' build check sum subtotal
  For i = 1 To Len(theZIP)
    checkDigit = checkDigit + Val(Mid(theZIP, i, 1))
  Next i
  ' POSTNET check digit is the single digit, that when added to the
  ' total of all the ZIP code's digits, makes the next multiple of 10.
  ' Concantenate the start bar, the ZIP code, check digit, & the stop bar.
  ' Format the output, AzaleaPOSTNET, using Azalea Software's POSTNET font.
  AzaleaPOSTNET = "s" + theZIP + Right(Str(100 - checkDigit), 1) + "s"
  ' yourContainer.text = AzaleaPOSTNET(yourString)
End Function