Undocumented Corner Column

by George Shepherd and Scot Wingo





Listing One

ISomeInterface* pSomeInterface = NULL;

HRESULT hr;

hr = CoCreateInstance(CLSID_SomeObject, NULL, CLSCTX_ALL, 

                                   IID_ISomeInterface, *pSomeInterface);

if(SUCCEEDED(hr)) {

   pSomeInterface->Function1();

   pSomeInterface->Function2();

   pSomeInterface->Release();

}



Listing Two

interface IConnectionPoint : IUnknown {

  HRESULT GetConnectionInterface(IID *pIID) = 0;

  HRESULT GetConnectionPointContainer(IConnectionPointContainer **ppCPC) = 0;

  HRESULT Advise(IUnknown *pUnk, DWORD *pdwCookie) = 0;

  HRESULT Unadvise(DWORD dwCookie) = 0;

  HRESULT EnumConnections(IEnumConnections **ppEnum) = 0;

};



Listing Three

interface IConnectionPointContainer : IUnknown {

  HRESULT EnumConnectionPoints(IEnumConnectionPoints **ppEnum) = 0;

  HRESULT FindConnectionPoint(REFIID riid, IConnectionPoint **ppCP) = 0;

};



Listing Four

class ATL_NO_VTABLE CConnectableObj : 

   public CComObjectRootEx<CComSingleThreadModel>,

   public CComCoClass<CConnectableObj, &CLSID_ConnectableObj>,

   public IConnectionPointContainerImpl<CConnectableObj>,

   public IDispatchImpl<IConnectableObj, &IID_IConnectableObj, 

                        &LIBID_CONNECTABLEOBJSVRLib>

{

 ...

};



Listing Five

[

   uuid(5BE91C40-BA0D-11D1-8CAA-D099043C7E50),

   version(1.0),

   helpstring("connectableobjsvr 1.0 Type Library")

]

library CONNECTABLEOBJSVRLib

{

   importlib("stdole32.tlb");

   importlib("stdole2.tlb");

   [

      uuid(21C85C43-0BFF-11d1-8CAA-FD10872CC837),

      helpstring("Events created from the control")

   ]

   dispinterface _DSomeEvents {

      properties:

      methods:

        [id(1)] void Event1([in]short x, [in] short y);

        [id(2)] void Event2([in] float x);

        [id(3)] void Event3();

   }

   [

      uuid(5BE91C4E-BA0D-11D1-8CAA-D099043C7E50),

      helpstring("ConnectableObj Class")

   ]

   coclass ConnectableObj

   {

      [default] interface IConnectableObj;

      [default, source] dispinterface _DSomeEvents;

   };

}



Listing Six

template <class T>

class CProxy_DSomeEvents : 

   public IConnectionPointImpl<T, &DIID__DSomeEvents, CComDynamicUnkArray>

{

public:

//methods:

//_DSomeEvents : IDispatch

public:

   void Fire_Event1(short x, short y)

   {   

      // gnarly code for calling 

      //   IDispatch::Invoke()

   }

   void Fire_Event2(float x) 

   {

      // gnarly code for calling 

      //   IDispatch::Invoke()

   }

   void Fire_Event3()

   {

      // gnarly code for calling 

      //   IDispatch::Invoke()

   }

};



Listing Seven

BEGIN_CONNECTION_POINT_MAP(CConnectableObj)

   CONNECTION_POINT_ENTRY(DIID__DSomeEvents)

END_CONNECTION_POINT_MAP()





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