Q153025: FIX: Microsoft Excel 95 Doesn’t Respond Correctly to GetObject

Article: Q153025
Product(s): Microsoft Visual Basic for Windows
Version(s): 4.0,7.0
Operating System(s): 
Keyword(s): kberrmsg kbprogramming
Last Modified: 03-MAR-2001

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
- Microsoft Excel for Windows 95, version 7.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

Attempting to use the GetObject function to return a reference to a running
instance of Microsoft Excel 95 results in the error 429:

  "OLE Automation server can't create object."

The identical code works correctly with a running instance of Microsoft Excel
5.0.

CAUSE
=====

Microsoft Excel 95 fails to correctly register itself in the Running Object
Table. The GetObject function can be used with the correct syntax to obtain a
currently running instance of Microsoft Excel 95 for use with OLE automation.

Microsoft Excel 95 requires one additional step to ensure that it will respond to
the OLE request. The code outlined below uses the SendMessage API to tell
Microsoft Excel 95 to listen for requests for objects.

RESOLUTION
==========

To work around this problem, follow these steps:

1. Add a single code module to the current project. Alternatively, if a code
  module already exists, it can be used instead.

2. Add the following code to the code module referred to in step 1: Const
  WM_USER = 1024

        Declare Function FindWindow Lib "user32" Alias "FindWindowA"_
        (ByVal lpClassName As String, ByVal lpWindowName As Long) As Long
        Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
        (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, _
        lParam As Long)
        As Long

        Sub WakeExcel()
             Dim hwnd As Long

             hwnd = FindWindow("XLMAIN", 0)
             If hwnd = 0 Then
                'no instances running
                Exit Sub
             End If
             SendMessage hwnd, WM_USER + 18, 0, 0
        End Sub

3. Add a call to the WakeExcel function so that it is called after a user may
  have started Microsoft Excel, but before the call to GetObject is made.

STATUS
======

Microsoft has confirmed this to be a bug in Microsoft Excel 95. This bug has
been fixed in Microsoft Excel 97.

MORE INFORMATION
================

Steps to Reproduce Problem
--------------------------

1. Start a new instance of Visual Basic 4.0. Form1 is created by default.

2. Add the following code to the Form_Click event of Form1:

        Private Sub Form_Click()
            Dim o As Object

            Set o = GetObject(, "Excel.Application")
            Set o = Nothing
        End Sub

3. Ensure that Microsoft Excel 95 is running.

4. Press the F5 key to run the application. Click the form once, and note the
  error outlined above.

REFERENCES
==========

For additional information, please see the following articles in the Microsoft
Knowledge Base:

  Q288902 INFO: GetObject and CreateObject Behavior of Office Automation
  Servers

  Q138723 XL7: Code to Access MS Excel Does Not Work in Version 7.0

Additional query words: GetActiveObject

======================================================================
Keywords          : kberrmsg kbprogramming 
Technology        : kbVBSearch kbExcelSearch kbAudDeveloper kbExcel700 kbExcel95Search kbVB400Search kbVB400
Version           : :4.0,7.0
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 1986-2002.