Knowledge Base

FIX: Insufficient Memory in Visual FoxPro on Fast Computers

Article ID: 179287

Article Last Modified on 9/30/2003

APPLIES TO

This article was previously published under Q179287

SYMPTOMS

When using a large table, cursor, or array (over 275 records) as the row source of a combo box, you may see the following error message:
There is not enough memory to complete this operation.

RESOLUTION

Here are four workarounds for this problem:

  • Upgrade to Visual FoxPro version 5.0.

    -or-
  • Use a grid control.

    -or-
  • Use a list box control.

    -or-
  • Limit the size of the underlying table, cursor, or array to 275 records or less.
The following code snippets illustrate implementation of the grid and list box workarounds based on the code example provided in the MORE INFORMATION section.

To use a grid instead of a combo box, replace the cbocombo class definition with the following code: 
   DEFINE CLASS cboCombo AS GRID
      LEFT = 10
      TOP = 25
      WIDTH=140
      HEIGHT=100
      VISIBLE=.T.
      RECORDSOURCETYPE=1
      RECORDSOURCE="Customer"
   ENDDEFINE
To use a list box instead of a combo box, replace the cbocombo class definition with the following code: 
   DEFINE CLASS cboCombo AS LISTBOX
      LEFT = 10
      TOP = 25
      WIDTH=140
      HEIGHT=100
      VISIBLE=.T.
      ROWSOURCETYPE=6
      ROWSOURCE="Customer.cust_id"
   ENDDEFINE

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article. This has been corrected in Visual FoxPro 6.0.

MORE INFORMATION

This behavior does not occur in Visual FoxPro 5.0 or 5.0a nor does this behavior occur with Visual FoxPro 3.0 when either of the following conditions is true:

  • The combo box Style property is set to 0 - Dropdown Combo.

    -or-

  • The combo box has been opened using the mouse.
The problem does occur under the following conditions:

  • The Combo box Style property is set to 2 - Dropdown List.

    -or-

  • The Combo box RowSourceType property is set to one of the following: 
          2 - Alias
      3 - SQL Statement
      4 - Query (.qpr)
      5 - Array
      6 [ASCII 150] Fields
    -or-

  • The Combo box is being navigated using the keyboard.

    -or-

  • Visual FoxPro 3.0 is being run on a computers with a clock speeds of 166 MHz or greater.

Steps to Reproduce Behavior

  1. Create a program called FrmCombo.prg using the following code: 

          ofrmcombo = CREATEOBJECT("frmcombo")
      ofrmcombo.VISIBLE = .T.
      ofrmcombo.ADDOBJECT("cboCombo1","cbocombo")
      ofrmcombo.ADDOBJECT("btnExit","cmdExit")

      READ EVENTS

      DEFINE CLASS frmcombo AS FORM
         CAPTION="Combo Form"
         TOP=0
         LEFT=0
         HEIGHT=150
         WIDTH=225
         PROCEDURE LOAD
            CREATE CURSOR customer (cust_id c(10))
            FOR i=1 TO 350
               INSERT INTO customer (cust_id) VALUES (SYS(2015))
            NEXT
            GO TOP
         ENDPROC
         PROCEDURE ACTIVATE
            THISFORM.REFRESH
         ENDPROC
      ENDDEFINE

      DEFINE CLASS cbocombo AS COMBOBOX
         LEFT = 10
         TOP = 25
         WIDTH = 140
         HEIGHT = 25
         VISIBLE = .T.
         INCREMENTALSEARCH=.F.
         CONTROLSOURCE="Customer.cust_id"
         ROWSOURCETYPE=6
         ROWSOURCE="Customer.cust_id"
         STYLE=2
      ENDDEFINE

      DEFINE CLASS cmdexit AS COMMANDBUTTON
         CAPTION = "Exit"
         LEFT = 155
         TOP = 25
         WIDTH = 50
         HEIGHT = 25
         VISIBLE = .T.
         PROCEDURE CLICK
            THISFORM.RELEASE
            CLEAR EVENTS
         ENDPROC
      ENDDEFINE

  2. Run the program. Once the form appears, move through the data in the combo box by holding down the DOWN ARROW key. The data appears to scroll through the combo box. At some point, the error occurs.

Keywords: kbbug kbfix kbprb KB179287


Send feedback to Microsoft

© Microsoft Corporation. All rights reserved.