DOCUMENT:Q190789  11-DEC-1999  [foxpro]
TITLE   :PRB: Access Method Fires for Properties that Do Not Exist
PRODUCT :Microsoft FoxPro
PROD/VER:WINDOWS:6.0
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

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

Accessing a property that does not exist in a class still fires the Access
method.

CAUSE
=====

This behavior permits the design of classes that support the addition of custom
properties at run-time using the AddProperty method. For example, the following
class definition adds a new property to the class at run-time when a
non-existent property is accessed:

      x = NewObject("myclass")

      ?x.NewProp  && New Property will be added to class.

      ?x.NewProp  && Note new property value.

      x.NewProp="Hello"  && Value assigned since property already exists.

      ?x.newprop

      DEFINE Class myclass as Custom
         PROCEDURE this_access(tcMember)
            IF ! PEMStatus(this,tcMember,5)
               this.AddProperty(tcMember)
            ENDIF
            RETURN this
         ENDPROC
      ENDDEFINE

STATUS
======

This behavior is by design.

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

Steps to Reproduce Behavior
---------------------------

Run the following code:

      x = NewObject('myclass')
      ?x.BogusProperty

      DEFINE class myclass as custom
         PROCEDURE this_access(tcMember)
            WAIT WINDOW tcMember
            RETURN this
         ENDPROC
      ENDDEFINE

The Access method fires before you receive the invalid property error.

Additional query words: kbVFp600 kbOOP

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Keywords          :  
Technology        : kbVFPsearch kbAudDeveloper kbVFP600
Version           : WINDOWS:6.0
Issue type        : kbprb

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