How to remove the system menu from an iconized application in Visual C++ (129224)

SUMMARY

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

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.
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 &amp; 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.

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
             .
      }

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
             .
      }

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);
             }
         }
      }