I am writing an MFC based dialog application (COM server) that contains a COM object (class CAutomateDlgAutoProxy : public CCmdTarget) for OLE automation. I have implemented an interface IAutomate which is working absolutely fine when called from another process. So far so good.

Now I want to support the outgoing interface IAutomateEvents. I have added INTERFACE_PART(CAutomateDlgAutoProxy, IID_IConnectionPointContainer, Automate) in the interface map along with INTERFACE_PART(CAutomateDlgAutoProxy, IID_IAutomate, Automate) and created a connection point also something like:

Server:

.h file:
   BEGIN_CONNECTION_PART(CAutomateDlgAutoProxy, AutomateEvents)
      CONNECTION_IID(IID_IAutomateEvents)
   END_CONNECTION_PART(AutomateEvents)

.cpp file:
BEGIN_CONNECTION_MAP(CAutomateDlgAutoProxy, CCmdTarget)
    CONNECTION_PART(CAutomateDlgAutoProxy, IID_IAutomateEvents, AutomateEvents)
END_CONNECTION_MAP()

The client is able to create the COM object and also QueryInterface for IConnectionPointContainer successfully.

Now here is the problem: when the client calls the following function the COM server returns the error DISP_E_BADINDEX:

Client:

// cpc is a valid connection point container pointer.
IConnectionPointPtr cp;
hr = cpc->FindConnectionPoint(__uuidof(IAutomateEvents), &cp);

The following code in the MFC file oledisp1.cpp is returning the error because itinfo is not 0:

STDMETHODIMP COleDispatchImpl::GetTypeInfo(UINT itinfo, LCID lcid,
    ITypeInfo** pptinfo)
{
    METHOD_PROLOGUE_EX_(CCmdTarget, Dispatch)
    ASSERT_POINTER(pptinfo, LPTYPEINFO);

    if (itinfo != 0)                // itinfo is not 0
        return DISP_E_BADINDEX;

    IID iid;
    if (!pThis->GetDispatchIID(&iid))
        return DISP_E_BADINDEX;

    return pThis->GetTypeInfoOfGuid(lcid, iid, pptinfo);
}

What is itinfo? Why it is not 0? I searched a lot but can’t find the details on IDispatch::GetTypeInfo() and specifically the itinfo parameter.

Thank you all!