FIX: GETPEM() Function Does Not Return the Correct ParentClass

ID: Q189772

The information in this article applies to:

Microsoft Visual FoxPro for Windows, versions 5.0, 5.0a

SYMPTOMS

If you use the GETPEM() function to return the value of the ParentClass property of an instantiated class, you might get incorrect results. The return value might be the ParentClass from another class in the class hierarchy, or might be empty when it should have a value.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This has been corrected in Visual FoxPro 6.0.

MORE INFORMATION

You use the GETPEM() function to return values of properties, or code from events/methods of any classes or objects in memory. The GETPEM() function requires two parameters. First, you pass it an object reference or the name of a class. Second, you pass it a property, event, or method name.

Steps to Reproduce Behavior

Run the following code from a program (.prg) file:


      CLEAR
      CLEAR ALL
      oMe = CREATEOBJECT( "Son" )
      cClass = oMe.CLASS

      DO WHILE NOT(EMPTY(cClass))
         ?cClass + ' was begotten by ' + GETPEM(cClass, "ParentClass")
         cClass = GETPEM(cClass, "ParentClass")
      ENDDO

      DEFINE CLASS granddad AS CUSTOM
      ENDDEFINE

      DEFINE CLASS Dad AS granddad
      ENDDEFINE

      DEFINE CLASS Son AS Dad
      ENDDEFINE

RESULT: If you run the code under Visual FoxPro 5.0x, the program returns the following to the desktop:

Son was begotten by Granddad
Granddad was begotten by

This is incorrect. The correct return values are:

Son was begotten by Dad
Dad was begotten by Granddad
Granddad was begotten by Custom
Custom was begotten by

Additional query words: kbVFp500abug kbVFp600fix kbOOP

Keywords :
Version : WINDOWS:5.0,5.0a
Platform : WINDOWS
Issue type : kbbug