Automatically Changing References to VBA Libraries

Mark is in a work environment that uses two versions of Excel—2002 and 2003. A problem arises when he opens a workbook with a macro in Excel 2003, which installs the VB library of Office 11, and then later someone tries to open the same workbook in Excel 2002, which gives an error when the macro tries to run because it cannot find the correct VBA library reference. Mark knows he can manually correct this by going to the VB editor and clearing the reference to the missing VBA library, but he wonders if there is any way to have the workbook check the Excel version automatically and update the VBA library reference accordingly.

One way to deal with this is to create and save the workbook using the earlier version of Excel. When it is opened in the later version of Excel, the reference to the VBA library will be automatically updated. Excel does the updates going to later versions, but it doesn't do them going to earlier versions.

This means, however, that even if the workbook is created in the earlier version of Excel, once it is opened and subsequently saved in the later version of Excel, users of the earlier version will have problems opening it.

The solution, according to some sources, is to resort to what is known as "late binding." This simply means that the macro is written so that it looks up specific functions only during run-time, not when the macro is saved. This is referenced a bit in the following Microsoft Knowledge Base article:

http://support.microsoft.com/?kbid=244167

You can try late binding techniques by opening the VBA editor and removing any references previously established. Then add code similar to the following near the start of your macro:

If Application.Version = "10.0" Then    'Excel 2002
    Dim oExcel As Object    'Apply late binding
    Set oExcel = CreateObject("Excel.Application")
End If
If Application.Version = "11.0" Then    'Excel 2003
    '
    ' Add whatever references you want for Excel 2003
    '
End If

At the end of the macro make sure that you set any defined objects (such as oExcel) to Nothing. A good example of code that is more robust than what is presented here can be found in these articles:

http://www.vbaexpress.com/kb/getarticle.php?kb_id=267
http://www.vbaexpress.com/kb/getarticle.php?kb_id=272