DOCUMENT:Q129224  26-MAR-2002  [visualc]
TITLE   :HOWTO: Remove the System Menu from an Iconized Application
PRODUCT :Microsoft C Compiler
PROD/VER::1.0,1.5,1.51,1.52,2.0,2.1,4.0,5.0,6.0
OPER/SYS:
KEYWORDS:kbcode kbMenu kbMFC KbUIDesign kbVC100 kbVC150 kbVC200 kbVC400 kbVC500 kbVC600 kbGrpDSM

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The information in this article applies to:

 - The Microsoft Foundation Classes (MFC), used with:
    - Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5, 1.51, 1.52 
    - Microsoft Visual C++, 32-bit Editions, versions 2.0, 2.1, 4.0 
    - Microsoft Visual C++, 32-bit Enterprise Edition, versions 5.0, 6.0 
    - Microsoft Visual C++, 32-bit Professional Edition, versions 5.0, 6.0 
    - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
    - Microsoft Visual C++.NET (2002) 
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SUMMARY
=======

There are two ways to remove the system menu of an application when a user
clicks an iconized application:

1. Override the main frame window's PreCreateWindow function to remove the
   WS_SYSMENU from the window's style field. However, this method removes the
   system menu altogether from the application.

2. Override the main frame window's OnSize method, and change the window style
   of the mainframe to either include or exclude the WS_SYSMENU style bit
   depending on user action. Use this technique if the user wants to remove the
   system menu when the application is iconized and add the system menu back to
   the application when the application is restored.

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

Method One
----------

To remove the system menu completely from the application, override the main
frame window's PreCreateWindow method as follows:

      BOOL CMainFrame::PreCreateWindow(CREATESTRUCT & cs)
      {
              // Call the base class version of PreCreateWindow, replace
             //  CMDIFrameWnd with CFrameWnd in the following line
             //  for an SDI application

              if (!CMDIFrameWnd::PreCreateWindow(cs))
                   return FALSE;

             // Remove the system menu style bit from the window

              cs.style &= ~WS_SYSMENU;
              return TRUE;
      }

Method Two
----------

The following steps and code fragments show how to remove the system menu when a
user clicks an iconized application. The system menu is restored when the
application is not iconized.

1. Declare a BOOLEAN public data member in the class declaration of CMainFrame.
   This data member determines if the system menu is enabled or not:

         // In an SDI application CMainFrame will be derived from CFrameWnd

         class CMainFrame : public CMDIFrameWnd
         {
         public:
            BOOL sys_menu_enabled;
                .
                .  // Existing class declarations
                .
         }

2. Modify the CMainFrame constructor to initialize the sys_menu_enabled data
   member function to TRUE:

         CMainFrame::CMainFrame()
         {
           //default the system menu to be enabled
           sys_menu_enabled = TRUE;
                .
                .  // Continue with normal constructor code, if any
                .
         }

3. Create a message handler for the WM_SIZE message for the CMainFrame class,
   and add the following code to the CMainFrame::OnSize message handler:

         void CMainFrame::OnSize(UINT nType, int cx, int cy)
         {
           // declare a local variable to hold the window style

              long window_style;

           //call base class's OnSize function,
           //If SDI application call CFrameWnd::OnSize()

           CMDIFrameWnd::OnSize(nType, cx, cy);

           //if user is minimizing or iconizing the application

           if (nType == SIZE_MINIMIZED)
           {
                // Get the main frame window's style
                 window_style = GetWindowLong(m_hWnd, GWL_STYLE);

                //Remove the system menu from the window's style
                 window_style &= ~WS_SYSMENU;

                //toggle the boolean data member to show sys menu disabled
                 sys_menu_enabled = FALSE;

                //set the style attribute of the main frame window
                SetWindowLong(m_hWnd, GWL_STYLE, window_style);
           }
           else
           {
                //if user is restoring the application and his system menu
                //is disabled,
                if ((nType == SIZE_RESTORED) || nType == SIZE_MAXIMIZED) &&
                   (!sys_menu_enabled))
                {
                    window_style = GetWindowLong(m_hWnd, GWL_STYLE);

                  //Add the system menu to the window's style
                    window_style |= WS_SYSMENU;

                 //toggle the boolean data member to show sys menu enabled
                   sys_menu_enabled = TRUE;

                   SetWindowLong(m_hWnd, GWL_STYLE, window_style);
                   SendMessage(WM_NCACTIVATE,TRUE);
                }
            }
         }

Additional query words:

======================================================================
Keywords          : kbcode kbMenu kbMFC KbUIDesign kbVC100 kbVC150 kbVC200 kbVC400 kbVC500 kbVC600 kbGrpDSMFCATL 
Technology        : kbAudDeveloper kbMFC
Version           : :1.0,1.5,1.51,1.52,2.0,2.1,4.0,5.0,6.0
Issue type        : kbhowto

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