Q183296: FIX: SETALL() Corrupts Properties of Custom Objects

Article: Q183296
Product(s): Microsoft FoxPro
Version(s): WINDOWS:3.0,3.0b,5.0,5.0a
Operating System(s): 
Keyword(s): kbvfp kbvfp500aBUG kbvfp500bug
Last Modified: 23-MAR-2000

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0, 5.0a 
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SYMPTOMS
========

When the SETALL() method is used to set a text property of custom objects,
subsequent use of the SETALL() method corrupts the property for all but the
first object.

RESOLUTION
==========

Create a procedure to set the properties of the objects in the container as
shown in the SetAllProp procedure below. Use this procedure in place of the
SETALL() method for setting the properties of custom objects.

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

     *-- Code begins here.
     CLEAR
     oX = CREATEOBJECT("Container")
     FOR counter = 1 TO 30
         oX.ADDOBJECT("x"+LTRIM(STR(counter)), "Example")
     ENDFOR

     =SetAllProp("MyProperty", "", "oX")
     =SetAllProp("MyProperty", "Example One - Test", "oX")
     ? oX.CONTROLS[1].MyProperty
     ? oX.CONTROLS[2].MyProperty
     ? oX.CONTROLS[3].MyProperty
     ? oX.CONTROLS[30].MyProperty
     ?  && Separator
     ?  && Separator

     *-- PROCEDURE SetAllProp
     *-- Step through the objects in a container and set the passed property
     *-- for each object.
     *-- Parameters: lcProperty  - The property to change.
     *--             lcValue     - The property's value.
     *--             lcContainer - The container containing the objects whose
     *--                           properties are to be changed.

     PROCEDURE SetAllProp()
        PARAMETERS lcProperty, lcValue, lcContainer

        *-- Load the object names into an array.
        =AMEMBERS(laObjects, EVALUATE(lcContainer), 2)

        *-- Step through the array and change the passed property for each
        *-- object.
        FOR liCounter = 1 TO ALEN(laObjects)
           lcCommand = lcContainer + "." + laObjects(liCounter) + "." + ;
             lcProperty + "=" + "'" + lcValue + "'"
           &lcCommand
        ENDFOR
     ENDPROC

     DEFINE CLASS Example AS CUSTOM
         MyProperty   = "Initial MyProperty"
     ENDDEFINE
     *-- Code ends here.

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

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

1. Run the following code:

        *-- Code begins here.
        CLEAR
        oX = CREATEOBJECT("Container")
        FOR counter = 1 TO 30
            oX.ADDOBJECT("x"+LTRIM(STR(counter)), "Example")
        ENDFOR

        *-- Round 1
        *-- Comment the following line and the properties are not corrupted.
        oX.SETALL("MyProperty", "")
        oX.SETALL("MyProperty", "Example One - Test")
        ? oX.CONTROLS[1].MyProperty
        ? oX.CONTROLS[2].MyProperty
        ? oX.CONTROLS[3].MyProperty
        ? oX.CONTROLS[30].MyProperty
        ?  && Separator
        ?  && Separator

        *-- Round 2
        *-- Uncommenting the following line just gives different corruption:
        *oX.SETALL("MyProperty", "")
        oX.SETALL("MyProperty", "Sample")
        oX.SETALL("MyProperty", "Sample2")
        oX.SETALL("MyProperty", "Sample3")
        oX.SETALL("MyProperty", "Example Two")
        ? oX.CONTROLS[1].MyProperty
        ? oX.CONTROLS[2].MyProperty
        ? oX.CONTROLS[3].MyProperty
        ? oX.CONTROLS[30].MyProperty

        DEFINE CLASS Example AS CUSTOM
            *-- Doesn't matter what the property is initially set to.
            MyProperty = "Initial MyProperty"
        ENDDEFINE
        *-- Code ends here

2. Read the comments in the code, make the appropriate changes, and run the code
  again.

3. When corruption occurs, the text properties of the custom class appear as
  random ASCII characters on the desktop.

NOTE: If your example displays more than three text properties, then a memory
error message, such as an illegal operation error, may appear.

Additional query words: GPF crash hang kbvfp600fix

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Keywords          : kbvfp kbvfp500aBUG kbvfp500bug 
Technology        : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP300b kbVFP500 kbVFP500a
Version           : WINDOWS:3.0,3.0b,5.0,5.0a
Issue type        : kbbug
Solution Type     : kbfix

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