Error Handling on external Macro - vba

Question

I am just wondering if it would be possible to do error handling on an external macro. Basically what I want to achieve is I have have thousands of excel workbooks that come in daily and I want to open each of them and run the macro from them (easily done just use the Application.run feature )
Application.Run ("'" & ActiveWorkbook & "'!Export")
What I want to achieve is I want to run error resolving function if that external macro incurs an error.
This is what I have so far
Dim str_SearchFile, str_FileName, str_SearchPath As String
Dim wb_WorkBook As Workbook
Application.ScreenUpdating = False
Application.DisplayAlerts = False
str_ThisBook = ActiveWorkbook.Name 'Set the current workbook for later reference
str_SearchPath = Sheets("Control Panel").Range("E2")
str_SearchFile = Sheets("Control Panel").Range("E2") & "\*.xls*" 'Sets the file type to search for
str_NextFile = Dir(str_SearchFile, vbDirectory) 'Sets the amount of files in the directory matching the criterea (.xls)
Do While Len(str_NextFile) > 0
On Error Resume Next
Set wb_WorkBook = Workbooks.Open(Filename:=str_SearchPath & "\" & str_NextFile, Password:="")
If Err.Number = 0 Then
On Error GoTo 0
Application.Run ("'" & str_NextFile & "'!Export")
str_FileName = str_SearchPath & "\Done" & "\" & str_NextFile
wb_WorkBook.Save
wb_WorkBook.Close
FileCopy (str_SearchPath & "\" & str_NextFile), str_FileName
Kill (str_SearchPath & "\" & str_NextFile)
End If
str_NextFile = Dir
Loop
Application.ScreenUpdating = True
Application.DisplayAlerts = True
End Sub
Any Advise is very welcome!
Thank you in advance

Answer 1

You won't be able to get this to work the way you are trying.
The MSDN on On Error Statement indicates that it (emphasis added):
Enables an error-handling routine and specifies the location of the
routine within a procedure; can also be used to disable an
error-handling routine.
The VBE Glossary defines a procedure as:
A named sequence of statements executed as a unit. For example,
Function, Property, and Sub are types of procedures. A procedure name
is always defined at module level. All executable code must be
contained in a procedure. Procedures can't be nested within other
procedures.
This means that calling error handling before calling the macro in the other book, will be ignored in the called macro (confirmed through testing).
The only way that you would be able to enable error handling would be to actually modify the code in the workbook prior to calling the macro... which is very complicated. For your reference, here is a webpage giving an example of editing project code from VBA.

Answer 2

The easiest way I would deal with this is to change your external workbook's "Export" sub into a function that returns a value - Say an integer.
What you can then do is put error trapping into that function and, based upon the outcome of the procedure it can return, say:
0 = All Went Well
1 = Failed to do XXX
2 = Failed to do YYY
You could then change your code to something like this:
Select Case Application.Run ("'" & str_NextFile & "'!Export")
Case 0
MsgBox "All Went Well"
Case 1
MsgBox "Failed to do XXX"
Case 2
MsgBox "Failed to do YYY"
End Select
This will allow you to put the error trapping where it belongs and know how the procedure ran.
hope this helps