FIX: SETALL() Corrupts Properties of Custom Objects

• Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0, 5.0a

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.

Additional query words: GPF crash hang kbvfp600fix

Keywords : kbVFp kbVFp500abug kbVFp500bug FxprgClassoop
Version : WINDOWS:3.0,3.0b,5.0,5.0a
Platform : WINDOWS
Issue type : kbbug