HOWTO: Replacing the Visual FoxPro Desktop with an App's Form

• Microsoft Visual FoxPro for Windows, versions 3.0, 5.0

SUMMARY

A Visual FoxPro application design may require that the Visual FoxPro desktop be hidden and the application's own forms occupy the entire Windows desktop area. This article explains how to do that.

This article adds the steps necessary to make the application's form the desktop. It concludes with the steps necessary to terminate the application and restore the Visual FoxPro desktop.

MORE INFORMATION

Step-by-Step Procedure

1. Start the application's form and establish the Visual FoxPro event handler with the READ EVENTS command. The code in the .prg file continues with the procedure needed to terminate the application's form, stop the Visual FoxPro event handler, and return to the Visual FoxPro desktop. After that code there is the function to hide the main Visual FoxPro window.

   ******************************************************************* ** Starter.prg Extreme minimum sample Code to start the application ******************************************************************* * DO FORM appform.scx READ EVENTS

   PROCEDURE back2vfp ** The application's form was activated from the desktop level as a ** desktop level form. The event handler is at the desktop level, and ** is equivalent to a property of the _SCREEN object, so it must be ** terminated by a method of the _SCREEN object. As no _SCREEN ** object members are visible (no command buttons, text boxes, etc.), ** a Timer event is used to clear events. The timer object is not ** visible, and doesn't need to be in order to be activated. ** To activate the Timer: Add it to the _SCREEN * _SCREEN.AddObject('oTime','MyTimer') && MyTimer is the

      **                                       current instance
      ** End of procedure Back2vfp
      **
      ** Class definition. The TIMER event is triggered after two seconds
      DEFINE CLASS MyTimer AS Timer
   
         Interval= 2000
   
         PROCEDURE Timer
            CLEAR EVENTS
            _SCREEN.RemoveObject('oTime')
         ENDPROC
      ENDDEFINE
      **
      ** End of extreme minimum sample Starter.prg*******************
      ***************************************************************
   
   

2. In the application's form, declare three properties of the form to serve as global references in the following function. Also place a command button or other object on the form, this object provides an event that can terminate the application. For this example, name the three properties FoxHWND, FoxGone, and ShowState. Name the command button Quit. Its Click event will contain code to terminate the form.

   CAUTION: If a template class is used to create a form, and its DeskTop property is set to .F., then setting the DeskTop property of the created form to .T. will have no effect. In that case, running the form will cause the main Visual FoxPro Window and the form within it to not be visible, which will require a rebooting in Windows 3.x, and potentially damaging files associated with the application.

   For more information about the behavior of the Desktop property, please see the following article(s) in the Microsoft Knowledge Base:

         ARTICLE-ID: Q141315
         TITLE     : Changing Subclassed Form's Desktop Property Has No Effect
   
      ** The following is the code to hide the Visual FoxPro desktop.
   
      **************************************************************
      * This function may be called in the Load Event of the
      * application's form that has these properties:
      *
      * WindowType = Modal,
      * AlwaysOnTop = True, and
      * DeskTop = True
      **************************************************************
   
      #DEFINE W32sDLL "W32SCOMB.DLL"
      #DEFINE W32DLL "USER32.DLL"
      IF "3.5" $ OS(1) OR "Windows 4" $ OS(1) OR "NT" $ OS(1)  &&
         cDLL = W32DLL
      ELSE
         cDLL = W32sDLL
      ENDIF
   
      DECLARE integer FindWindow IN &cDLL integer, string
      DECLARE Integer ShowWindow IN &cDLL Integer, Integer
   
      SW_MAXIMIZE = 3
      SW_SHOWNORMAL = 1
      SW_SHOWMINIMIZED = 2
      SW_SHOWGONE = 0
   
      ThisForm.showstate = SW_SHOWNORMAL
   
      NullPointer = 0
      ThisForm.FoxHWND = FindWindow(NullPointer, _SCREEN.Caption)
   
      * Hide the Main Visual FoxPro Window
      ThisForm.FoxGone = ShowWindow(ThisForm.FoxHWND, SW_SHOWGONE)
   
      ** The next command is optional - it shows the successful
      ** execution of this function's code.
      ** =MessageBox("Visual FoxPro Desktop is hidden...")
   
      **************************************************************
      ** End of function.
      **************************************************************
   
   

3. Place the following code in the Click event of the Quit command button.

   * Clear the form ThisForm.Release * * Restore the Visual FoxPro desktop ThisForm.FoxGone = ShowWindow(ThisForm.FoxHWND, ThisForm.showstate) * * Terminate the READ EVENTS with a CLEAR EVENTS two seconds after * restoring the Visual FoxPro desktop

      DO Back2vfp    && Procedure found in the calling program Starter.prg
   
   

Caveats

If this code is placed in a project and built into an application, the user will receive the following error messages in a Locate File dialog box:

   Unable to find Unknown FINDWINDOW
   Locate, Ignore, Ignore All, Cancel

   Unable to find Unknown SHOWWINDOW.
   Locate, Ignore, Ignore All, Cancel

• Ignore the errors, and the project will build without a problem.

  -or-

• Add a program to the project that references the FINDWINDOW and SHOWWINDOW as a procedure or a function.