FIX: Microsoft Excel 95 Doesn't Respond Correctly to GetObject (153025)

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:

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

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

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.

MORE INFORMATION

Steps to Reproduce Problem

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

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

Ensure that Microsoft Excel 95 is running.
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:

288902 INFO: GetObject and CreateObject Behavior of Office Automation Servers

138723 XL7: Code to Access MS Excel Does Not Work in Version 7.0