Using IDispEventImpl

#pragma warning (disable : 4146)

// Paths to required MS OFFICE files (replace "MSO.DLL" and "MSWORD.OLB" with the actual paths to those files...)
#define _MSDLL_PATH "MSO.DLL"
// Delete the *.tlh files when changing import qualifiers
#import _MSDLL_PATH rename("RGB", "MSRGB") rename("DocumentProperties", "WordDocumentProperties") raw_interfaces_only

#import "C:\Program Files\Common Files\Microsoft Shared\VBA\VBA6\VBE6EXT.OLB" raw_interfaces_only

#define _MSWORDOLB_PATH "MSWORD.OLB"
#import _MSWORDOLB_PATH rename("ExitWindows", "WordExitWindows") rename("FindText", "WordFindText") raw_interfaces_only

#pragma warning (default : 4146)

// Note #import doesn't generate a LIBID (because we don't use 'named_guids')
// so we have to do it manually
namespace Word
{
   struct __declspec(uuid("00020905-0000-0000-C000-000000000046"))
      /* library */ Library;
};

class ATL_NO_VTABLE CNotSoSimple : 
   public CComObjectRootEx<CComSingleThreadModel>,
   public CComCoClass<CNotSoSimple, &CLSID_NotSoSimple>,
   public IDispatchImpl<ISwitch, &IID_ISwitch, &LIBID_ATLEVENTHANDLINGLib>,
   // Note inheritance from IDispEventImpl
   public IDispEventImpl</*nID*/ 1, CNotSoSimple,
            &__uuidof(Word::ApplicationEvents2),
            &__uuidof(Word::Library), /*wMajor*/ 8, /*wMinor*/ 1>

{
public:
   CNotSoSimple()
   {
   }

DECLARE_REGISTRY_RESOURCEID(IDR_NOTSOSIMPLE)

DECLARE_PROTECT_FINAL_CONSTRUCT()

BEGIN_COM_MAP(CNotSoSimple)
   COM_INTERFACE_ENTRY(ISwitch)
   COM_INTERFACE_ENTRY(IDispatch)
END_COM_MAP()

   CComPtr<Word::_Application> m_pApp;

   // Event handlers
   // Note the __stdcall calling convention and 
   // dispinterface-style signature   
   void __stdcall OnQuit()
   {
      Stop();
   }

   void __stdcall OnDocChange()
   {
     ATLASSERT(m_pApp != NULL);

      // Get a pointer to the _Document interface on the active document
      CComPtr<Word::_Document> pDoc;
      m_pApp->get_ActiveDocument(&pDoc);

      // Get the name from the active document
      CComBSTR bstrName;
      if (pDoc)
        pDoc->get_Name(&bstrName);

      // Create a display string
      CComBSTR bstrDisplay(_T("New document title:\n"));
      bstrDisplay += bstrName;

      // Display the name to the user
      USES_CONVERSION;
      MessageBox(NULL, W2CT(bstrDisplay), _T("IDispEventImpl : Active Document Changed"), MB_OK);
   }

// Note the mapping from Word events to our event handler functions.
BEGIN_SINK_MAP(CNotSoSimple)
   SINK_ENTRY_EX(/*nID =*/ 1, __uuidof(Word::ApplicationEvents2), /*dispid =*/ 3, OnDocChange)
   SINK_ENTRY_EX(/*nID =*/ 1, __uuidof(Word::ApplicationEvents2), /*dispid =*/ 2, OnQuit)
END_SINK_MAP()

// ISwitch
public:

   STDMETHOD(Start)()
   {
      // If we already have an object, just return
      if (m_pApp)
         return S_OK;

      // Create an instance of Word's Application object
      HRESULT hr = m_pApp.CoCreateInstance(__uuidof(Word::Application), NULL, CLSCTX_SERVER);
     if (FAILED(hr))
        return hr;

     ATLASSERT(m_pApp != NULL);

      // Make the Word user interface visible
      m_pApp->put_Visible(true);

      // Note call to advise
      // Forge a connection to enable us to receive events
      DispEventAdvise(m_pApp);

      return S_OK;
   }

   STDMETHOD(Stop)()
   {
      // Check we have an object to unadvise on
      if (!m_pApp)
         return S_OK;

      // Note call to unadvise
      // Break the connection with the event source
      DispEventUnadvise(m_pApp);

      // Release the Word application
      m_pApp.Release();

      return S_OK;
   }
};