DOCUMENT:Q221749  09-JUL-1999  [foxpro]
TITLE   :FIX: Top Level Forms with Menus Allow Access to Datasession 0
PRODUCT :Microsoft FoxPro
PROD/VER:WINDOWS:5.0,5.0a,6.0
OPER/SYS:
KEYWORDS:kbContainer kbCtrl kbvfp500aBUG kbvfp600 kbvfp600bug KbDBFDBC kbVS600sp3fix kbGrpDSFox

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Visual FoxPro for Windows, versions 5.0, 5.0a, 6.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

You have an application based on a top-level form, which runs several child
forms that are called from a menu. One of these forms contains a grid. If the
table or cursor that is the grid's RecordSource is closed and then another form
is instantiated, the system datasession will be selected and Visual FoxPro will
be placed in an unstable state.

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.

For more information about Visual Studio service packs, please see the following
articles in the Microsoft Knowledge Base:

   Q194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why

   Q194295 HOWTO: Tell That Visual Studio 6.0 Service Packs Are Installed

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

The system datasession is used by Visual FoxPro to open the Foxuser resource
file, form and class library files, report files, and so forth. It should not be
accessible to the user under any circumstances. If the system datasession
becomes selected, closing tables in it will cause Visual FoxPro to produce
errors or terminate.

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

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

   PUBLIC oGrid, oMain
      * Make Form2 - it must be an SCX.
      MODIFY FORM form2 NOWAIT
      = aselobj(xx,1)
      xx[1].ShowWindow = 1   && Make it In Top-Level
      KEYBOARD '{y}'
      Release window 'form designer - form2.scx'

      * Create a table and add some data
      CREATE TABLE TEMP(TEMP1 C(6), TEMP2 C(6))  
      INSERT INTO TEMP (TEMP1, TEMP2) ;
      VALUES ("FIELD1", "FIELD2")

      CLOSE DATA ALL && Clean Start, no open tables open to start.

      oMain = CREATEOBJECT('MAIN')  && Top-level form
      oMain.Show
      READ events
      WAIT window 'DataSession Number is: '+alltr(str(set('datasession')))
      * Let's avoid problems and go back to datasession 1
      SET DATASESSION TO  1
      CLOSE DATA ALL

      DEFINE CLASS grid1 AS form
          ShowWindow = 1
          Caption = "GRID1"
          Name = "GRID1"
          ADD OBJECT grid1 AS grid WITH ;
              ColumnCount = 2, ;
              Name = "Grid1"
      ENDDEFINE

      DEFINE CLASS main AS form
          ShowWindow = 2
          Caption = "Click on Grid Form menu item"
          Name = "MAIN"

          PROCEDURE Show
              LPARAMETERS nStyle
              DO MenuProc WITH thisform,.T.
          ENDPROC

          PROCEDURE queryunload
              Clear events
          ENDPROC
      ENDDEFINE

      PROC MenuProc
          LPARAMETERS oFormRef, getMenuName
         	DEFINE MENU MyMenu IN (oFormRef.name) BAR
      	DEFINE PAD Pad1 OF MyMenu PROMPT "Grid Form" COLOR SCHEME 3 ;
      	    KEY ALT+C, ""
      	ON SELECTION PAD Pad1 OF MyMenu ;
      	    DO Proc1
      	DEFINE PAD Pad2 OF MyMenu PROMPT "Form 2" COLOR SCHEME 3 ;
      	    KEY ALT+F, ""
      	ON SELECTION PAD Pad2 OF MyMenu ;
      	    DO Proc2
      	Activate MENU MyMenu NOWAIT
      ENDPROC

      PROCEDURE Proc1
          SELECT 0
          USE TEMP alias TEMP
          SELECT TEMP
          oGrid=create('grid1')
          oGrid.show
          oMain.Caption = 'Click on Form2 menu item'
      ENDPROC

      PROCEDURE Proc2
          SELECT TEMP
          USE
          oGrid.release
          DO form form2
          oMain.Caption = "Click on Close Box to close =====>"
      ENDPROC

2. Click on the Grid Form menu pad.

3. Click on the Form 2 menu pad.

4. Click on the close box in the main form.

5. A WAIT WINDOW will be displayed with the current Datasession, which will be
   0.

(c) Microsoft Corporation 1999, All Rights Reserved. Contributions by Jim
Saunders, Microsoft Corporation.


Additional query words:

======================================================================
Keywords          : kbContainer kbCtrl kbvfp500aBUG kbvfp600 kbvfp600bug KbDBFDBC kbVS600sp3fix kbGrpDSFox kbDSupport 
Technology        : kbVFPsearch kbAudDeveloper kbVFP500 kbVFP600 kbVFP500a
Version           : WINDOWS:5.0,5.0a,6.0
Issue type        : kbbug
Solution Type     : kbfix

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 1999.