DOCUMENT:Q183164  30-MAR-1998  [vbwin]
TITLE   :BUG: For..Each Loop in ActiveX Component Causes Errors
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:WINDOWS:5.0,97sp2,97sp3
OPER/SYS:WINDOWS
KEYWORDS:vb5all VBKBAX kberrmsg

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

 - Microsoft Visual Basic Learning, Professional, and Enterprise Editions
   for Windows, version 5.0
 - Microsoft Visual Studio versions 97sp2, 97sp3
---------------------------------------------------------------------

SYMPTOMS
========

When using an ActiveX DLL created in Visual Basic, you may receive one of
the following errors if the ActiveX component contains a For..Each loop
that iterates through a Visual Basic collection:

   Run-time error '48':
   Error in loading DLL

   -or-

   Run-time error '-2147319765 (8002802b)':
   Automation Error

This problem occurs when a For..Each loop is executed in an ActiveX DLL.
For..Each loops elsewhere do not exhibit this problem.

CAUSE
=====

This problem typically occurs after calling the DLL at least twice. The
first call into the DLL does not execute code that uses a For..Each loop
but the second call does. The error occurs during the second call. See the
"Steps to Reproduce Behavior" section below for more information.

RESOLUTION
==========


 - Use a For..Next loop in place of the For..Each loop.

   -or-

 - Create your own collection class, an example of which can be found in
   the Visual Basic Books Online. Refer to the topic "Creating Your Own
   Collection Classes."

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products
listed at the beginning of this article. We are researching this
bug and will post new information here in the Microsoft Knowledge
Base as it becomes available.

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

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

1. Create a new ActiveX DLL project in Visual Basic.

2. Click Project1 Properties from the Project menu and set the Project Name
   to "AutoErr1."

3. Copy the following code to the Class1 module:

      Public Sub Method1()
         Dim col As New Collection
         Dim obj As Object
         For Each obj In col
         Next obj
      End Sub

4. Click "Make AutoErr1.dll" from the File menu to create the DLL file.

5. Quit Visual Basic. You may optionally save the project files.

6. Start Microsoft Excel 97 and create a new workbook. Press the ALT+F11
   keys to start the Visual Basic editor.

7. Click Module from the Insert menu to add a standard module. Add the
   following code to the new module:

      Private Sub Test48()
         ' First call into dll
         Dim o as Object
         Set o = CreateObject("AutoErr1.Class1")
         Set o = Nothing
         ' Second call into dll
         Set o = CreateObject("AutoErr1.Class1")
         o.Method1 ' calls method that uses For..Each loop
         set o = Nothing
      End Sub

8. Press the F8 key to step through the Sub's code and note that the
   following error occurs when calling Method1:

      Run-time error '48':
      Error in loading DLL

The following steps demonstrate how to reproduce the Automation error using
Visual Basic as the client. Note that these steps may not reproduce the
error on some machines.

1. Follow steps 1 through 5 above to create the AutoErr1.dll.

2. Start a new Standard EXE project in Visual Basic. Form1 is
   created by default.

3. Place 2 CommandButtons (Command1 and Command2) on Form1.

4. Copy the following code to the Form1 module:

      Private Sub Command1_Click()
         ' First call into dll
         Dim o As Object
         Set o = CreateObject("AutoErr1.Class1")
         Set o = Nothing
      End Sub

      Private Sub Command2_Click()
         ' Second call into dll
         Dim o As Object
         Set o = CreateObject("AutoErr1.Class1")
         o.Method1
         Set o = Nothing
      End Sub

5. Press the CTRL+F5 keys to run the project.

6. Click Command1.

7. Click Command2. Note that the following error may occur when calling
   Method1:

      Runtime-error '-2147319765 (8002802b)':
      Automation Error

Additional query words: element not found
======================================================================
Keywords          : vb5all VBKBAX kberrmsg
Version           : WINDOWS:5.0,97sp2,97sp3
Platform          : WINDOWS
Issue type        : kbbug
Solution Type     : kbpending

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

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