DOCUMENT:Q236625  17-JUL-1999  [foxpro]
TITLE   :PRB: TABLEREVERT Fails with Row Buffering and List Box RowSource
PRODUCT :Microsoft FoxPro
PROD/VER:WINDOWS:5.0,5.0a,6.0
OPER/SYS:
KEYWORDS:kbDatabase kbOOP kbvfp500 kbvfp500a kbvfp600 KbDBFDBC kbGrpDSFox

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

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

SYMPTOMS
========

Fields do not revert to unedited values after issuing a TABLEREVERT command.

CAUSE
=====

This behavior occurs when Optimistic or Pessimistic Row Buffering is enabled and
the table being reverted to unedited values serves as the RowSource for a list
box with the RowSourceType set to 6 - Fields.

RESOLUTION
==========

Set the buffer mode of the table to one of the following values:

+-------------------------------------------+
| Buffer Mode | Description                 | 
+-------------------------------------------+
| 4           | Pessimistic table buffering | 
+-------------------------------------------+
| 5           | Optimistic table buffering  | 
+-------------------------------------------+

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

This problem does not happen with drop-down list-type combo boxes.

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

1. Create a program file named 'CBODEMO.PRG' using the following code:

   PUBLIC ox
   ox=CREATEOBJECT('testfrm')
   ox.SHOW

   DEFINE CLASS testfrm AS FORM

      TOP = 0
      LEFT = 0
      HEIGHT = 237
      WIDTH = 325
      DOCREATE = .T.
      CAPTION = "Form1"
      NAME = "Form1"
      editing = .F.

      ADD OBJECT command1 AS COMMANDBUTTON WITH ;
         TOP = 192, ;
         LEFT = 120, ;
         HEIGHT = 27, ;
         WIDTH = 84, ;
         CAPTION = "Edit", ;
         NAME = "Command1"

      ADD OBJECT command2 AS COMMANDBUTTON WITH ;
         TOP = 192, ;
         LEFT = 228, ;
         HEIGHT = 27, ;
         WIDTH = 84, ;
         CAPTION = "Close", ;
         NAME = "Command2"

      ADD OBJECT text1 AS TEXTBOX WITH ;
         CONTROLSOURCE = "testtbl.charfldb", ;
         HEIGHT = 23, ;
         LEFT = 24, ;
         TOP = 60, ;
         WIDTH = 100, ;
         NAME = "Text1"

      ADD OBJECT list1 AS listbox WITH ;
         ROWSOURCETYPE = 6, ;
         ROWSOURCE = "testtbl.charflda", ;
         HEIGHT = 145, ;
         LEFT = 132, ;
         TOP = 24, ;
         WIDTH = 181, ;
         NAME = "List1"

      PROCEDURE LOAD
         PUBLIC MULTI_LOCK_STAT
         MULTI_LOCK_STAT=SET('multilocks')
         IF !USED('testtbl')
            CREATE CURSOR testtbl (charflda c(10), charfldb c(10))
            SELECT testtbl
            INSERT INTO testtbl VALUES ('1000000000','1000000000')
            INSERT INTO testtbl VALUES ('2000000000','0000000000')
         ENDIF
         IF MULTI_LOCK_STAT='OFF'
            SET MULTILOCKS ON
         ENDIF
         =CURSORSETPROP('Buffering',3,'testtbl')
      ENDPROC

      PROCEDURE UNLOAD
         SET MULTILOCKS &MULTI_LOCK_STAT
      ENDPROC
      
      PROCEDURE command1.REFRESH
         IF THIS.PARENT.editing
            THIS.CAPTION='Save'
         ELSE
            THIS.CAPTION='Edit'
         ENDIF
      ENDPROC

      PROCEDURE command1.CLICK
         IF THIS.CAPTION = "Edit"
            THISFORM.editing = .T.
         ELSE
            =TABLEUPDATE(.F.,.F.,"testtbl")
            THISFORM.editing = .F.
         ENDIF
         THISFORM.REFRESH
         IF THISFORM.editing
            THISFORM.text1.SETFOCUS
         ENDIF
      ENDPROC

      PROCEDURE command2.CLICK
         IF THIS.CAPTION = "Close"
            THISFORM.RELEASE
            USE IN testtbl
         ELSE
            =TABLEREVERT(.T.,"testtbl")
            THISFORM.editing = .F.
         ENDIF
         IF USED('testtbl')
            THISFORM.REFRESH
         ENDIF
      ENDPROC

      PROCEDURE command2.REFRESH
         IF THIS.PARENT.editing
            THIS.CAPTION='Revert'
         ELSE
            THIS.CAPTION='Close'
         ENDIF
      ENDPROC

      PROCEDURE text1.REFRESH
         IF THIS.PARENT.editing
            THIS.ENABLED=.T.
         ELSE
            THIS.ENABLED=.F.
         ENDIF
      ENDPROC

      PROCEDURE list1.CLICK
         THISFORM.REFRESH
      ENDPROC
   ENDDEFINE

2. From the Command window, type DO CBODEMO.

3. Click on the first item of the list box.

4. Click the Edit button to enable the text box.

5. Change the value displayed in the text box.

6. Click the Revert button, and note that the value displayed in the text box
   did not revert to its unedited value.

7. Change the following line of code:

   =CURSORSETPROP('Buffering',3,'testtbl')

so that it now reads:

   =CURSORSETPROP('Buffering',5,'testtbl')

8. Repeat steps 2 through 6 and note that the value displayed in the text box
   reverts to its unedited value.

(c) Microsoft Corporation 1999, All Rights Reserved.
Contributions by John Desch, Microsoft Corporation


Additional query words: ComboBox Buffering Controls

======================================================================
Keywords          : kbDatabase kbOOP kbvfp500 kbvfp500a kbvfp600 KbDBFDBC kbGrpDSFox 
Technology        : kbVFPsearch kbAudDeveloper kbVFP500 kbVFP600 kbVFP500a
Version           : WINDOWS:5.0,5.0a,6.0
Issue type        : kbprb
Solution Type     : kbpending

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

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