Q299528: FIX: Focus Moves From Textbox In Grid Despite RETURN 0

Article: Q299528
Product(s): Microsoft FoxPro
Version(s): 5.0,5.0a,6.0
Operating System(s): 
Keyword(s): kbOOP kbvfp500aBUG kbvfp500bug kbvfp600bug kbGrpDSFox kbCodeSnippet kbvfp500xSearch kbv
Last Modified: 11-FEB-2002

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

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

SYMPTOMS
========

RETURN 0 and NODEFAULT are often used to prevent default behavior in a control
event. In Microsoft Visual FoxPro (VFP) 5.0 and 6.0, these commands do not
prevent focus from leaving a text box in a grid column when they are used in the
Valid event of the control.

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products that are
listed at the beginning of this article.

This problem was corrected in Microsoft Visual FoxPro version 7.0 for Windows.

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

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

1. In VFP 5.0 or 6.0, paste the following code in a new project:

  *!* FIX: Q299528 Focus Moves From Textbox In Grid In Spite Of RETURN 0 In VALID
  CREATE CURSOR cur1 (f1 C(5), f2 i)
  INSERT INTO cur1 VALUES ('xxx',1)
  INSERT INTO cur1 VALUES ('yyy',2)
  GO TOP

  PUBLIC oform1
  oform1=CREATEOBJECT("form1x")
  oform1.SHOW
  RETURN

  DEFINE CLASS form1x AS FORM
  	AUTOCENTER = .T.
  	CAPTION = "Form1"
  	NAME = "Form1"

  	ADD OBJECT grdcustomer AS GRID WITH ;
  		COLUMNCOUNT = 2, ;
  		LEFT = 12, ;
  		RECORDSOURCE = "cur1", ;
  		RECORDSOURCETYPE = 1, ;
  		TOP = 12, ;
  		NAME = "grdCustomer", ;
  		Column1.CONTROLSOURCE = "cur1.f1", ;
  		Column1.NAME = "Column1", ;
  		Column2.CONTROLSOURCE = "cur1.f2", ;
  		Column2.NAME = "Column2"

  	ADD OBJECT text1 AS TEXTBOX WITH ;
  		HEIGHT = 25, ;
  		LEFT = 132, ;
  		TOP = 220, ;
  		WIDTH = 60, ;
  		NAME = "Text1"

  	PROC INIT
  		THISFORM.grdcustomer.Column1.REMOVEOBJECT('text1')
  		THISFORM.grdcustomer.Column1.ADDOBJECT('text1','textboxx')
  		THISFORM.grdcustomer.Column1.text1.VISIBLE = .T.
  	ENDPROC

  	PROCEDURE DESTROY
  		USE IN cur1
  	ENDPROC
  ENDDEFINE

  DEFINE CLASS textboxX AS TEXTBOX
  	BORDERSTYLE = 0
  	MARGIN = 0
  	NAME = "Text1"
  	PROCEDURE VALID
  		IF !"x"$THIS.VALUE
  			WAIT WINDOW 'Needs to have an "x"' TIME 1
  			RETURN 0
  		ENDIF
  	ENDPROC
  ENDDEFINE

2. Save and run the code (the name is unimportant).

3. A form with a grid and a text box is shown. Using the mouse, click in the
  second row of the grid, in the "YYY" text box.

4. Left-click into the textbox at the bottom of the form.

At this point in the code, the Valid event of the text box in the grid displays a
message box that says that a value of "X" is required. Note, however, that after
the WAIT WINDOW clears, focus is now in the text box on the form, instead of in
the text box in the grid. This occurs although the Valid event retuned 0, which
should have prevented focus from leaving the grid text box.

If you run the same code in VFP 7.0 and follow the same steps, focus does not
leave the grid text box.

NOTE: The LostFocus event of text boxes in a grid also has this problem. This was
not fixed in VFP 7.0. It is advised that you use the Valid event to prevent
focus from moving as detailed in the previous code.

Additional query words:

======================================================================
Keywords          : kbOOP kbvfp500aBUG kbvfp500bug kbvfp600bug kbGrpDSFox kbCodeSnippet kbvfp500xSearch kbvfp700fix kbfixlist
Technology        : kbVFPsearch kbAudDeveloper kbVFP500 kbVFP600 kbVFP500a
Version           : :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 1986-2002.