Problem with a collection of event sinks

=?Utf-8?B?Sm9obg==?= <>
Wed, 14 Mar 2007 09:09:13 -0700
I have created an object that contains a collection of inner objects, the
main object needs to respond to the events of these inner objects within the

I have created a template class based on IDispEventImpl, which sets up the
event sink for the inner objects within the collection and forwards the calls
to the main object.

template <class T>
class CObjEventSink : public IDispEventImpl<0, CObjEventSink,
&DIID__IEventSink, &LIBID_someLib, 1, 0>
    CObjEventSink(T* pOwner) : m_pOwner(pOwner) {}

        SINK_ENTRY_EX(0, DIID__IEventSink, 0x1, OnEvent)

    void STDMETHODCALLTYPE OnEvent() {m_pOwner->OnEvent();}

    T* m_pOwner;

In the main objects header file I define two vectors, one for the objects
and another for the event sinks.

// define a collection of objects and event sinks
std::vector<CComVariant> m_vecObjs;
std::vector< CObjEventSink <CSomeObj> > m_vecObjSinks;

In the implementation file of the main object I create the collection of the
inner objects, event sinks and establish the connections.

for (i=0; i<10; i++) {
// create inner objects
CComPtr<ISomeObj> pobj;

// create event sink for inner object

Now here is my problem when I fire the event from one of the inner objects
the program crashes in the connection point proxy class

HRESULT Fire_Event()
  T * pThis = static_cast<T *>(this);
  CComPtr<IUnknown> punkConnection = m_vec.GetAt(iConnection);

And when I step into the code to find out the exact point of failure it???s in
atlcomcli.h at the Addref() in the following code;

CComPtrBase(T* lp) throw()
p = lp;
if (p != NULL)

Now, when I create only one instance of the inner object and one event sink
(not as a collection) as in the following. The code works perfectly the event
is fired and handeled by the main object.

// main objects header file
CComPtr<ISomeObj> m_Obj; // single object
CObjEventSink <CSomeObj> m_ObjSink; // single sink

// main objects constructor
CMainObj() : m_ObjSink (this)

// main objects final construct

My question is am I not declaring the vector of event handlers properly, why
would it work with a single object but not a collection of objects?

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