FIX: Poor Performance With Forms Containing Many Objects

• Microsoft Visual FoxPro for Windows, version 6.0

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.

Steps to Reproduce Behavior

REFERENCES

Additional query words: kbVFP6QFE

Keywords : kbOOP kbPerfMon kbVFp600 kbVFp600bug kbVS600sp3fix kbVFP600QFE
Version : WINDOWS:6.0
Platform : WINDOWS
Issue type : kbbug