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Q134621: How to Find Out If an Object Is in a Container or Not

Article: Q134621
Product(s): Microsoft FoxPro
Version(s): WINDOWS:3.0
Operating System(s): 
Keyword(s): 
Last Modified: 15-FEB-2000

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, version 3.0 
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SUMMARY
=======

This article describes how to use the TYPE() function to find out whether or not
an object is contained in another object.

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

It is sometimes necessary to know if an object is in a container, and perform an
action according to the way an instance of the object is created. For example, a
form can be placed on the desktop or in a formset, and the program can perform
different tasks depending on the container.

The Parent property of an object references the container object of a control.
Use the TYPE() function to determine if an object has a parent. For example:

     IF TYPE ('This.Parent')= "0"  && The object has a container
        ? This.Parent.Name
     ENDIF

The following example illustrates this method using a command button. If the
control is placed in a toolbar, the Visible property of the toolbar is set to
false (.F.) when the button is released. To run this example, copy and paste the
code into a program (.PRG) file. When the toolbar is displayed, click the Close
button. The toolbar is hidden before it is released.

Sample Code
-----------

  PUBLIC oTB1,oFrm1  && Define public variables
  oTb1=CREATE('tbmytool') && Create an instance of the toolbar object
  oTb1.SHOW
  oFrm1=CREATE('Frmmyform') && Create an instance of the form object
  oFrm1.SHOW

  DEFINE CLASS cmdQuit AS COMMANDBUTTON
     PROCEDURE CLICK
        RELEASE THISFORM  && Release either the form or the toolbar
     ENDPROC
     PROCEDURE DESTROY  && Called when the object is released
        IF TYPE('This.parent')="O"
           IF THIS.PARENT.BASECLASS="Toolbar"
              THIS.PARENT.VISIBLE = .F. && Hides the toolbar
              =MESSAGEBOX('Toolbar is hidden')
           ENDIF
        ENDIF
     ENDPROC

  ENDDEFINE

  DEFINE CLASS tbMyTool AS TOOLBAR
     ADD OBJECT cmdNew AS COMMANDBUTTON
     ADD OBJECT cmdClose AS cmdQuit
  ENDDEFINE

  DEFINE CLASS frmmyform AS FORM
     ADD OBJECT cmdForm AS cmdQuit
  ENDDEFINE

Additional query words: VFoxWin form set

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Keywords          :  
Technology        : kbVFPsearch kbAudDeveloper kbVFP300
Version           : WINDOWS:3.0

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