DOCUMENT:Q200854  11-JUN-2002  [visualc]
TITLE   :HOWTO: Trapping Server's Menu Commands in Composite Menu Bar
PRODUCT :Microsoft C Compiler
PROD/VER::5.0,6.0
OPER/SYS:
KEYWORDS:kbole kbActiveX kbCOMt kbContainer kbMenu kbMFC kbVC500 kbVC600 kbGrpDSMFCATL kbArchite

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The information in this article applies to:

 - The Microsoft Foundation Classes (MFC), included with:
    - 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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NOTE: Microsoft Visual C++ NET (2002) supported both the managed code model that is provided by the .NET Framework and the unmanaged native Windows code model. The information in this article applies to unmanaged Visual C++ code only.

SUMMARY
=======

The composite menu bar is a shared menu composed of menu groups from both a
container application and an in-place activated server application. Sometimes,
the container application may want to trap the server's menu commands that are
shown in the composite menu bar to carry out its own operations. This article
illustrates a way to accomplish this task.

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

When the server is in-place activated, the COleClientItem::OnInsertMenus()
function will be called to install the composite menu. When the server is
deactivated, the COleClientItem::OnRemoveMenus() function will be called to
remove the composite menu. We can make use of these two functions to determine
the menu selection when the composite menu is shown.

In the following sample code, Microsoft Word is the server application in an
AppWizard-generated MFC container application. The steps to trap the Word's
Edit/Paste menu command follow:

1. Add a public member variable named m_hSharedMenu of type HMENU to the
   container's CWinApp-derived class. Initialize its value to NULL in the
   constructor function. It is public because it will be accessed by functions
   in the COleClientItem-derived class.

2. Override both the OnInsertMenus() and OnRemoveMenus() functions of the
   COleClientItem-derived class. Set the value of the m_hSharedMenu variable to
   the HMENU of the composite menu in the OnInsertMenus() function, and assign
   NULL to m_hSharedMenu in the OnRemoveMenus() function.

      // CContainerCntrItem is a COleClientItem-derived class.
      void CContainerCntrItem:OnInsertMenus(
          CMenu* pMenuShared, LPOLEMENUGROUPWIDTHS lpMenuWidths)
      {
          ((CContainerApp *) AfxGetApp())->m_hSharedMenu =
              pMenuShared->GetSafeHmenu();
          COleClientItem::OnInsertMenus(pMenuShared, lpMenuWidths);
      }

      void CContainerCntrItem::OnRemoveMenus(CMenu* pMenuShared)
      {
          ((CContainerApp *) AfxGetApp())->m_hSharedMenu = NULL;
          COleClientItem::OnRemoveMenus(pMenuShared);
      }

3. Override PreTranslateMessage() of the CWinApp-derived class to trap the
   selection of the Edit/Paste menu command.

      // CContainerApp is a CWinApp-derived class.
      BOOL CContainerApp::PreTranslateMessage(MSG* pMsg)
      {
          if (pMsg->message == WM_COMMAND && m_hSharedMenu)
          {
           // The drop-down menu in the menu bar is 0-based. To simplify the
           // code, we make an assumption that the Edit menu is at position
           // one, instead of looping through the main menu to find out the
           // position of the Edit menu.
           char str[80];
           ::GetMenuString(m_hSharedMenu, 1, str, sizeof(str),
               MF_BYPOSITION);
           TRACE("submenu = %s\n", str);

           HMENU hsub = ::GetSubMenu(m_hSharedMenu, 1);

           // Get the menu string of the selected menu item.
           ::GetMenuString(hsub, pMsg->wParam, str, sizeof(str),
               MF_BYCOMMAND);
           TRACE("menu item = %s\n", str);

           // Do something when Edit\Paste menu command is selected.
           if (lstrcmp(str, "&Paste\tCtrl+V") == 0)
               TRACE("Word's Edit\\Paste menu command is selected\n");
           return TRUE;
       }
       else
           return CWinApp::PreTranslateMessage(pMsg);
      }

I, Yeong-Kah Tam, give Microsoft Corporation permission to publish my name as a
contributor to this article.

Additional query words:

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Keywords          : kbole kbActiveX kbCOMt kbContainer kbMenu kbMFC kbVC500 kbVC600 kbGrpDSMFCATL kbArchitecture 
Technology        : kbAudDeveloper kbMFC
Version           : :5.0,6.0
Issue type        : kbhowto

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