INFO: Application Object Protected in Custom VFP COM Servers (195533)

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: