DOCUMENT:Q162682 19-FEB-2002 [foxpro] TITLE :PRB: Visual FoxPro Form Is Inaccessible with Foundation READ PRODUCT :Microsoft FoxPro PROD/VER::3.0,3.0b,5.0,6.0 OPER/SYS: KEYWORDS:kbvfp kbvfp300 kbvfp300b kbvfp500 kbvfp600 ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0, 6.0 ------------------------------------------------------------------------------- SYMPTOMS ======== When a Visual FoxPro form is run within a converted FoxPro 2.x application and program execution falls back to the Foundation READ, then some or all of the controls on the form do not respond to keyboard or mouse input. RESOLUTION ========== Use a READ EVENTS to set up the wait state, rather than a Foundation READ, which uses a READ VALID. STATUS ====== This behavior is by design. MORE INFORMATION ================ In order to create a wait state in FoxPro 2.x, the Foundation READ was used. This allowed an application using the FoxPro run time to continue to execute while waiting for user input--selection of a menu option, for example. In Visual FoxPro, the Foundation READ is no longer necessary, but the wait state must still be established to create an application, which uses the run time. This is now done with the READ EVENTS command. If a Visual FoxPro form is instantiated, either with DO FORM or CREATEOBJECT() within an application employing a Foundation READ, the form's controls may be inaccessible. This occurs if program execution is halted at the Foundation READ (READ VALID command) when the Visual FoxPro form is instantiated. Steps to Reproduce Behavior --------------------------- 1. Run the following code from a program (.prg) file: * Beginning of program file ******************************************************************** * This simulates a FoxPro 2.x application with a menu, screen, and * Foundation READ. A Visual FoxPro form has been added to this also, * simulating what occurs if such a form is added to an existing * FoxPro 2.x type application, which is run under Visual FoxPro. * SET PROCEDURE TO SYS(16) lValid = .F. && Sets the Foundation READ variable * Establish menu SET SYSMENU TO DEFINE PAD do_screen OF _MSYSMENU PROMPT "Do Screen" DEFINE PAD do_form OF _MSYSMENU PROMPT "Do Form" DEFINE PAD do_exit OF _MSYSMENU PROMPT "Exit" ON SELECTION PAD do_screen OF _MSYSMENU DO do__screen ON SELECTION PAD do_form OF _MSYSMENU DO show__form ON SELECTION PAD do_exit OF _MSYSMENU DO do__exit * Establish Foundation READ or READ EVENTS READ VALID lValid && Comment this and * READ EVENTS && uncomment this for workaround SET PROC TO SET SYSMENU TO DEFAULT PROCEDURE do__screen DEFINE WINDOW wind1 FROM 1,1 TO 20,30 ; FLOAT GROW CLOSE SYSTEM TITLE "Read Screen" ACTIVATE WINDOW wind1 @ 10,8 GET gnChoice DEFAULT 1 ; FUNCTION '*3 \!Close me' SIZE 3,12 READ CLEAR WINDOW ENDPROC PROCEDURE do__exit lValid = .T. CLEAR EVENTS CLEAR READ ALL MOUSE CLICK ENDPROC PROCEDURE show__form PUBLIC ox ox = CREA('form1') ox.SHOW() ENDPROC DEFINE CLASS form1 AS FORM CAPTION = "VFP Form" ADD OBJECT command1 AS COMMANDBUTTON WITH ; TOP = 120, ; LEFT = 130, ; HEIGHT = 25, ; CANCEL = .T. ,; CAPTION = "Close me" PROCEDURE command1.CLICK THISFORM.RELEASE() ENDPROC ENDDEFINE * * End of program file 2. Click "Do Screen" on the menu. A FoxPro 2.x style READ screen is displayed. Click the "Close me" button to close the screen. 3. Click "Do Form" on the menu. A Visual FoxPro form is instantiated and displayed. Click the "Close me" button to attempt to close the form. The button will not be accessible. Close the form by clicking on the Close [x] button in the upper right corner or by pressing Ctrl+F4. 4. Select Exit from the menu. To demonstrate the workaround, comment out the "READ VALID lValid" line in the above example by starting the line with an asterisk, remove the asterisk from the beginning of the "* READ EVENTS" line, and rerun the program. The screen still works as before, and now the "Close me" command button on the form is also accessible. REFERENCES ========== For additional information on the Foundation READ and READ EVENTS, please see the following article in the Microsoft Knowledge Base: Q87694 Menu Appears, Then Application Exits to Operating System Additional query words: ====================================================================== Keywords : kbvfp kbvfp300 kbvfp300b kbvfp500 kbvfp600 Technology : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP300b kbVFP500 kbVFP600 Version : :3.0,3.0b,5.0,6.0 ============================================================================= 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 2002.