INFO: Application Object Protected in Custom VFP COM Servers

ID: Q195533

The information in this article applies to:

Microsoft Visual FoxPro for Windows, version 6.0

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
Version :
Platform :
Issue type : kbinfo