Running a Macro in a Number of Workbooks

If you have quite a number of workbooks that you want to process through the use of macros, you may be tempted to place the processing macro within each workbook (as an Auto_Open macro), and then write some type of routine to load each workbook, in turn, and save it.

While this may sound good in theory, it won't work in practice. Why? Because when you open a workbook under macro control, the Auto_Open macro in the workbook being opened will not automatically run. There are three ways around this problem.

The first is to redo your macro so that you don't rely on Auto_Open macros in each workbook. If the Auto_Open macro in each workbook is the same, then why not simply move the code to a separate procedure in the controlling workbook? For instance, let's say you were using code that followed this process:

Sub MyMacro()
    Dim J As Integer
    Dim sTarget As String

    Application.ScreenUpdating = False
    For J = 1 To 999
        sTarget = "Book" & Format(J, "000") & ".xls"
        Workbooks.Open sTarget
        'Auto_Open runs here
        Workbooks(sTarget).Save
    Next J
    Application.ScreenUpdating = True
End Sub

This won't work, for reasons already explained. One solution is to simply move the common Auto_Open code into another procedure, and then call it after opening the workbook, as shown here:

Sub MyMacro()
    Dim J As Integer
    Dim sTarget As String

    Application.ScreenUpdating = False
    For J = 1 To 999
        sTarget = "Book" & Format(J, "000") & ".xls"
        Workbooks.Open sTarget
        Workbooks(sTarget).Activate
        DoCommonCode
        Workbooks(sTarget).Save
    Next J
    Application.ScreenUpdating = True
End Sub

Sub DoCommonCode()
    'Common code goes here
End Sub

This approach works fine, provided the routine is the same that will be run on all your different workbooks. If the routines are different in each workbook, then you can force VBA to run the Auto_Open macro. This is done by using the RunAutoMacros method right after opening the workbooks:

Workbooks.Open sTarget
ActiveWorkbook.RunAutoMacros xlAutoOpen

Given this approach, you could easily come up with a macro that would simply open each workbook (so the Auto_Open macros could run) and then save them. Such a macro would appear as follows:

Sub RunAutoOpenMacrosInBooks()
    Dim J As Integer
    Dim sTarget As String

    Application.ScreenUpdating = False
    For J = 1 To 999
        sTarget = "Book" & Format(J, "000") & ".xls"
        On Error Resume Next
        Workbooks.Open sTarget
        Windows(sTarget).Activate
        With ActiveWorkbook
            If .Name <> ThisWorkbook.Name Then
                .RunAutoMacros xlAutoOpen
                .Save
                .Close
            End If
        End With
    Next i
    Application.ScreenUpdating = True
End Sub

A third, and even better, approach is to not rely upon Auto_Open macros in each of your workbooks. Instead, rely on the Workbook_open event as a way to run your macro. The Workbook_open event is triggered automatically, regardless of whether the workbook is opened manually or in another macro. The code that the event contains is run automatically, just as you would expect of an Auto_Open macro.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (2278) applies to Microsoft Excel 97, 2000, 2002, and 2003.