Q151901: PRB: StatusBar Pane Enabled by Default

Article: Q151901
Product(s): Microsoft C Compiler
Version(s): winnt:
Operating System(s): 
Keyword(s): kbMFC KbUIDesign kbVC400 kbVC410 kbGrpDSMFCATL kbMFCCtrlBar
Last Modified: 06-MAY-2001

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The information in this article applies to:

- The Microsoft Foundation Classes (MFC), used with:
   - Microsoft Visual C++ 32-bit Edition, versions 4.0, 4.1 
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SYMPTOMS
========

When a non-default pane is added to the StatusBar, this pane is automatically
enabled even if it does not have an Update UI handler.

CAUSE
=====

This behavior is different than the behavior in earlier versions of MFC where
the pane was automatically disabled if there was no Update UI handler.

RESOLUTION
==========

To disable the pane, unless it is enabled by a handler, add an Update UI handler
for the pane to the CMainFrame class of the application that disables the pane.

STATUS
======

This behavior is by design.

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

In certain situations the pane can be disabled by default, such as when the pane
is displaying the status associated with a Document or the View. In these
situations, you should disable the pane if no Document/View is open.

To disable the pane by default, add an Update UI handler for this pane to
CMainFrame. Add an update UI handler in the Document or View that updates the
pane depending on the status.

When a Document/View is open, then the update UI handler in the Document/View
will update the pane depending on its state. When all documents are closed, the
Update handler in CMainFrame will disable the pane.

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

      /* Compile options needed: default
     */ 
     // Following code disables a pane in the StatusBar with ID,
     // ID_MYPANE in the CMainFrameClass.

     // MainFrm.h : interface of the CMainFrame class
     ...
     class CMainFrame : public CMDIFrameWnd
     {
     ...
         //}}AFX_MSG
         afx_msg void OnUpdateMypane(CCmdUI* pCmdUI);
         DECLARE_MESSAGE_MAP()
     };

     // MainFrm.cpp : implementation of the CMainFrame class
     ...

     BEGIN_MESSAGE_MAP(CMainFrame, CMDIFrameWnd)
         //{{AFX_MSG_MAP(CMainFrame)
     ...
         //}}AFX_MSG_MAP
         ON_UPDATE_COMMAND_UI(ID_MYPANE, OnUpdateMypane)
     END_MESSAGE_MAP()

     static UINT indicators[] =
     {
         ID_SEPARATOR,           // status line indicator
         ID_MYPANE,             //String resource with this ID in resources
         ID_INDICATOR_CAPS,
         ID_INDICATOR_NUM,
         ID_INDICATOR_SCRL,
     };

     ...
     void CMainFrame::OnUpdateMypane(CCmdUI* pCmdUI)
     {
         pCmdUI->Enable(FALSE);

     }

Additional query words: 4.00 4.10 CStatusBar enable

======================================================================
Keywords          : kbMFC KbUIDesign kbVC400 kbVC410 kbGrpDSMFCATL kbMFCCtrlBar 
Technology        : kbAudDeveloper kbMFC
Version           : winnt:
Issue type        : kbprb

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