Q279777: BUG: FOR EACH Reference Fails To Release Automation Server

Article: Q279777
Product(s): Microsoft FoxPro
Version(s): 5.0,5.0a,6.0
Operating System(s): 
Keyword(s): kbAutomation kbvfp500 kbvfp500a kbvfp500aBUG kbvfp600 kbvfp600bug kbGrpDSFox kbDSupport
Last Modified: 13-DEC-2000

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 5.0, 5.0a, 6.0 
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SYMPTOMS
========

If you use a FOR EACH loop to iterate through a collection of objects in an
Automation Server, the server may not release correctly when you release the
variables.

RESOLUTION
==========

To resolve this problem, use the CLEAR ALL command to clear all memory,
including any hidden references. This may not be an optimal solution, however,
because you may be depending on variables that should remain in memory, such as
an application object.

Another possible resolution is to find other ways to refer to the collection. For
example, given the following code, you want to set a value for each cell in a
range:

  loRange = loWorkbook.ActiveSheet.Range("A1:D4,E5:H8")

  *!* This loop will show the bug.
  FOR EACH loCell in loRange
     loCell.Value = "Fred"
  ENDfor
        
  *!* This single command will not.
  loRange.Value = "Fred"

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article.

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

Steps to Reproduce Behavior
---------------------------

To see this behavior with Microsoft Excel and Microsoft Windows NT and Microsoft
Windows 2000, perform the following steps:

1. Open the Task Manager, and confirm that no instance of Excel is currently
  running.

2. Open Visual FoxPro, and paste the following code into a .prg file:

  LOCAL loExcel, lcFile, loWorkbook, lcRange, loCell, loRange

  lcFile = GETFILE('XLS')

  IF NOT EMPTY(lcFile)
     loExcel = CREATEOBJECT('Excel.Application')
     loExcel.Visible = .t.

     loWorkbook = loExcel.Workbooks.Open(lcfile)
     lcRange = loExcel.Selection.Address(.F., .F., 1)
     loRange = loWorkbook.ActiveSheet.Range(lcRange)

     FOR EACH loCell IN loRange
        *!* Empty loop
     NEXT

     loCell = .NULL.
     loRange = .NULL.

     loExcel.Quit()
  ENDif

3. Run the program, and then select an Excel file.

Note that although the Excel window goes away, an instance of Excel.exe is left
in the Task Manager. If you comment out the FOR EACH loop, the instance releases
properly.

Additional query words:

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Keywords          : kbAutomation kbvfp500 kbvfp500a kbvfp500aBUG kbvfp600 kbvfp600bug kbGrpDSFox kbDSupport 
Technology        : kbVFPsearch kbAudDeveloper kbVFP500 kbVFP600 kbVFP500a
Version           : :5.0,5.0a,6.0
Issue type        : kbbug
Solution Type     : kbpending

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