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Q132568: PRB: Creating Instance of OLE Control Causes Exception Error

Article: Q132568
Product(s): Microsoft FoxPro
Version(s): 
Operating System(s): 
Keyword(s): 
Last Modified: 20-AUG-1999

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, version 3.0 
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SYMPTOMS
========

When creating simultaneous instances of OLE automation objects, Visual FoxPro
displays this error:

  OLE error Code

Under some circumstances, an exception error is generated in one of the server
applications. This behavior occurs when one of the OLE objects is an OLE control
(OCX).

CAUSE
=====

This error results from creating an instance of an OLE control with the
following syntax:

  Oobject1=CREATEOBJECT(<olecustomcontrol>)

OLE Automation objects (OCX) are not designed to be standalone automation
servers.


WORKAROUND
==========

Place the OLE control in an OLE container instead of creating an instance of the
OLE control. The following example illustrates this method. It uses the outline
control that ships with Visual FoxPro.

Example code
------------

  oMyform=CREATEOBJECT('new_form')
  oMyform.SHOW

  * The following lines add three items to the outline control.

  oMyform.myoutline.ADDITEM('VFP',0)
  oMyform.myoutline.indent(0)=1
  oMyform.myoutline.ADDITEM('Samples',1)
  oMyform.myoutline.indent(1)=2
  oMyform.myoutline.ADDITEM('Controls',2)
  oMyform.myoutline.indent(2)=3
  READ EVENTS

  * Form class definition. The form contains a command button and an
  * olecontrol

  DEFINE CLASS new_form AS FORM
     AUTOCENTER=.T.
     BACKCOLOR=RGB(192,192,192)
     WIDTH= 220
     HEIGHT= 200
     CAPTION= "Using the outline control"
     ADD OBJECT myoutline AS outlinecontrol
     ADD OBJECT mycmd AS cmdquit WITH TOP=120, LEFT=80
  ENDDEFINE

  * Defines the Ole container control. The OLE class is MSOutl. Outline.
  * The Outline control is used.
  DEFINE CLASS outlinecontrol AS OLECONTROL
     OLECLASS = "MSOutl.Outline"
     LEFT=12
     Top=12
     Width=170
     Height=80
     FontSize=10
     FontName="Arial"
     FontBold=.F.
     FontItalic=.T.
  ENDDEFINE

Class Definition for Command Button
-----------------------------------

  * Class definition for the command button. When users click the command
  * button, the form is released.

  DEFINE CLASS cmdquit AS COMMANDBUTTON
     Width=40
     Height=25
     Caption = "Quit"

     PROCEDURE CLICK
        RELEASE ThisForm
        CLEAR EVENTS
     ENDPROC
  ENDDEFINE

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

Code to Reproduce Behavior
--------------------------

  ON ERROR ? "-------------------------> "+message()
  oObj1=CREATEOBJECT("Word.Basic")
  oObj2= CREATEOBJECT("Excel.Sheet")
  oObj5= CREATEOBJECT('msoutl.outline')
  ON ERROR

Additional query words: VFoxWin crash

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Keywords          :  
Technology        : kbVFPsearch kbAudDeveloper kbVFP300

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