Q197510: FIX: Poor Performance with Forms Containing Many Objects

Article: Q197510
Product(s): Microsoft FoxPro
Version(s): WINDOWS:6.0
Operating System(s): 
Keyword(s): kbOOP kbPerfMon kbvfp600 kbvfp600bug kbVS600sp3fix kbvfp600QFE
Last Modified: 05-OCT-1999

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The information in this article applies to:

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

Instantiating a form or container that contains many objects, may be much slower
in Visual FoxPro version 6.0 than in Visual FoxPro version 5.0.

If the form contains a pageframe with multiple pages, page activation may be much
slower in Visual FoxPro 6.0 than in Visual FoxPro 5.0.

Normally, this behavior does not manifest itself unless the form or container
instantiated contains at least several hundred objects.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article.This bug was corrected in Visual Studio 6.0 Service
Pack 3..

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

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

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

     * This program creates a number of forms that each
     * add a pageframe at run-time. Each page activates
     * after the pageframe is instantiated. The number of forms,
     * pages in the pageframe, and text boxes on each page
     * are set from the #DEFINE statements. The times in seconds for
     * each form to add its objects, and activate each page
     * are echoed to the Debug Output window. The total time in
     * seconds for all forms is echoed last.
        
     #DEFINE NO_OF_FORMS          10
     #DEFINE NO_OF_PAGES          20
     #DEFINE NO_OF_TEXTBOXES      10

     DEBUG
     DEBUGOUT ''

     PUBLIC gnStart
     gnStart = SECONDS()
     FOR lni = 1 TO NO_OF_FORMS
        lcfrmName = 'oform'+ALLTR(STR(lni))
        &lcfrmName = CREATEOBJECT('perfform')
        &lcfrmName..CAPTION = SUBSTR(lcfrmName,2)
        &lcfrmName..SHOW()
     ENDFOR

     FOR lnj = 1 TO _SCREEN.FORMCOUNT
        lcfrmName = 'oform'+ALLTR(STR(lnj))
        &lcfrmName..SHOW()
        lnstart = SECONDS()
        FOR lnk = 1 TO &lcfrmName..pf1.PAGECOUNT
           &lcfrmName..pf1.ACTIVEPAGE = lnk
        ENDFOR
        DEBUGOUT 'Form '+ ALLTR(STR(lnj)) + ;
           ':                 '+alltr(str(SECONDS() - lnstart,5,2))
     ENDFOR
    DEBUGOUT 'All forms:             '+alltr(str(SECONDS() - gnStart,5,2))
     READ EVENTS

      DEFINE CLASS perfform AS FORM
       HEIGHT = 350
       ADD OBJECT pf1 AS PAGEFRAME WITH ;
         PAGECOUNT = 0
       PROC pf1.INIT()
          THIS.HEIGHT = THIS.PARENT.HEIGHT - 5
          FOR lnj = 1 TO NO_OF_PAGES
             THIS.ADDOBJECT('pg'+ALLTR(STR(lnj)), 'pg')
          ENDFOR
       ENDPROC
     ENDDEFINE

     DEFINE CLASS pg AS PAGE
       PROC ACTIVATE()
          IF TYPE('this.cntPage') # 'O'
             THIS.ADDOBJECT("cntPage", "cnPageContainer")
          ENDIF
       ENDPROC
     ENDDEFINE

     DEFINE CLASS cnpagecontainer AS CONTAINER
        NAME = "cnpagecontainer"
        VISIBLE = .T.
        Top = 5
        ADD OBJECT cmd1 AS COMMANDBUTTON WITH ;
           LEFT = 180, ;
           TOP = 20, ;
           CAPTION = 'Quit', ;
           VISIBLE = .T.

        PROC INIT()
           THIS.HEIGHT = THIS.PARENT.PARENT.HEIGHT - 20
           THIS.WIDTH = THIS.PARENT.PARENT.WIDTH - 5
           FOR lnp = 1 TO NO_OF_TEXTBOXES
              THIS.ADDOBJECT('lbl'+ALLTR(STR(lnp)), 'label')
              WITH THIS.CONTROLS(lnp+1)
                 .LEFT = 10
                 .TOP = 25*(lnp-1)+ 2
                 .WIDTH = 80
                 .NAME = 'lbl'+ALLTR(STR(lnp))
                 .VISIBLE = .T.
              ENDWITH
           ENDFOR
           FOR lnq = lnp TO (2 * lnp) - 2
              THIS.ADDOBJECT('txt'+ALLTR(STR(lnq)), 'textbox')
              WITH THIS.CONTROLS(lnq+1)
                 .HEIGHT = 23
                 .LEFT = 90
                 .TOP = 25*(lnq-lnp)+ 2
                 .WIDTH = 80
                 .NAME = 'txt'+ALLTR(STR(lnq))
                 .VISIBLE = .T.
              ENDWITH
           ENDFOR
        ENDPROC

        PROC cmd1.CLICK
           gnStart = SECONDS()
           CLEAR EVENTS
        ENDPROC
     ENDDEFINE

2. Note the "All forms:" time in the Debug Output window. This will be around
  five times higher in Visual FoxPro 6.0 than in Visual FoxPro 5.0.

This example is specifically designed to exhibit the behavior. As written, it
instantiates over 2000 objects and activates 200 pages. The impact of this issue
on your application is likely to be much less, since most applications do not
simultaneously instantiate 200 pages with 10 objects each.

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

REFERENCES
==========



Additional query words: kbVFP6QFE

======================================================================
Keywords          : kbOOP kbPerfMon kbvfp600 kbvfp600bug kbVS600sp3fix kbvfp600QFE 
Technology        : kbVFPsearch kbAudDeveloper kbVFP600
Version           : WINDOWS:6.0
Issue type        : kbbug
Solution Type     : kbfix

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