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Q195533: INFO: Application Object Protected in Custom VFP COM Servers

Article: Q195533
Product(s): Microsoft FoxPro
Version(s): 
Operating System(s): 
Keyword(s): kbCOMt kbvfp600
Last Modified: 12-AUG-1999

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, version 6.0 
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SUMMARY
=======

The application object in Microsoft Visual FoxPro version 6.0 custom COM servers
is protected.

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

In Visual FoxPro 5.0, the application object was exposed by default in all
custom COM servers. In Visual FoxPro 6.0, the application object is now
"protected," so that it cannot be accessed outside a particular instance of the
object.

To show this, build the following code into a Visual FoxPro COM .exe:

Sample Code
-----------

     **********Server Code*******************
     DEFINE CLASS Test1 AS CUSTOM OLEPUBLIC

        PROCEDURE retapp
           RETURN THIS.APPLICATION
        ENDPROC
        PROCEDURE retapp2
           RETURN _VFP.APPLICATION
        ENDPROC
     ENDDEFINE
     **********End Server Code***************

     **********Begin Client Code************
     oX=CREATEOBJECT("SERVTEST.TEST1")
     oY=oX.retapp &&Works
     oZ=oX.retapp2 &&Works
     ?oY.Name
     ?oZ.Name
     ?oX.Application.Name &&Errors Occur
     *********End Client Code***************

The first two references work because they access the application object from
within the instance of the object through a method and return the result to the
client.

The last reference "oX.Application.Name" tries to reference the Application
object directly from the client. This returns the following error message:

  OLE error code 0x80020006: Unknown name

Additional query words:

======================================================================
Keywords          : kbCOMt kbvfp600 
Technology        : kbVFPsearch kbAudDeveloper kbVFP600
Issue type        : kbinfo

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

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