Two Outlook COM Add-ins and connection points

Question

Hi, I have an application that requires that we install two Outlook COM add-ins. I want to send an event from one COM add-in to the other. So I chose to use ATL connection points. While I can use connection points without a problem in one add-in and capture events, I cannot seem to fire the same event to the other add-in. They are both COM DLL's and are loaded in the same process. I have done this before with other applications, but I seem not to be able to fire an event in one add-in and receive that connection point event in the other add-in within Outlook. Is this a security thing within Outlook? I have tried all the free threaded options, but it seems not to make a difference. Does anybody have any suggestions?

Thanks in advance.

Tom -

Answer 1

Yep, I should have attached some code. Late night :)! I have attached some example code. It fails because if cannot find the connection point connection. I did try to go old school without ATL, but I get the same result.

There is not any failure code, just cannot find connection.

CComPtr<IUnknown> sp = m_vec.GetAt(nConnectionIndex); /// <<<< ALWAYS RETURNS 0 FAILS HERE

The code ...

//////////
/// DLL  #1 (add-in #1)
////////////

// Header

class ATL_NO_VTABLE CSiteDown :
    public CComObjectRootEx<CComSingleThreadModel>,
    public CComCoClass<CSiteDown, &CLSID_SiteDown>,
    public IConnectionPointContainerImpl<CSiteDown>,
    public IDispatchImpl<ISiteDown, &IID_ISiteDown, &LIBID_paddinLib, /*wMajor =*/ 1, /*wMinor =*/ 0>,
    public CProxy_ISiteDownEvents<CSiteDown>
{
public:
    CSiteDown()
    {
    }

    DECLARE_REGISTRY_RESOURCEID(115)


    BEGIN_COM_MAP(CSiteDown)
        COM_INTERFACE_ENTRY(ISiteDown)
        COM_INTERFACE_ENTRY(IDispatch)
        COM_INTERFACE_ENTRY(IConnectionPointContainer)
    END_COM_MAP()

    BEGIN_CONNECTION_POINT_MAP(CSiteDown)
        CONNECTION_POINT_ENTRY(__uuidof(_ISiteDownEvents))
    END_CONNECTION_POINT_MAP()


    DECLARE_PROTECT_FINAL_CONSTRUCT()

    HRESULT FinalConstruct()
    {
        return S_OK;
    }

    void FinalRelease()
    {
    }


public:

    STDMETHOD(EnableErrorState)(VARIANT_BOOL vbEnable);

};

// CPP #1
STDMETHODIMP CSiteDown::EnableErrorState(VARIANT_BOOL vbEnable)
{
    AFX_MANAGE_STATE(AfxGetStaticModuleState());

    Fire_EnableEvent(vbEnable);
    return S_OK;
}

// Events #1
// Events_CP.h

VOID Fire_EnableEvent(VARIANT_BOOL b)
{
    T* pT = static_cast<T*>(this);
    int nConnectionIndex;
    CComVariant* pvars = new CComVariant[2];
    int nConnections = m_vec.GetSize();

    for (nConnectionIndex = 0; nConnectionIndex < nConnections; nConnectionIndex++)
    {
        pT->Lock();
        ///////////////////////////
        /// DOES NOT RECOGNIZE CONNECTION IN THE ADDIN #2
        ///////////////////////////
        CComPtr<IUnknown> sp = m_vec.GetAt(nConnectionIndex);  ///  <<<< ALWAYS RETURNS 0  FAILS HERE
        pT->Unlock();
        IDispatch* pDispatch = reinterpret_cast<IDispatch*>(sp.p);
        if (pDispatch != NULL)
        {
            pvars[0].vt = VT_BOOL;
            pvars[0].boolVal = b;
            DISPPARAMS disp = { pvars, NULL, 1, 0 };
            pDispatch->Invoke(88, IID_NULL, LOCALE_USER_DEFAULT, DISPATCH_METHOD, &disp, NULL, NULL, NULL);
        }
    }
    delete[] pvars;
}

//////////
/// DLL  #2 (add-in #2)
////////////

// Header

BEGIN_COM_MAP(CDown)
    COM_INTERFACE_ENTRY2(IDispatch, IRibbonCallback)
    COM_INTERFACE_ENTRY(_FormRegionStartup)
    COM_INTERFACE_ENTRY(IDown)
    COM_INTERFACE_ENTRY(_IDTExtensibility2)
    COM_INTERFACE_ENTRY(IRibbonExtensibility)
    COM_INTERFACE_ENTRY(IRibbonCallback)
    COM_INTERFACE_ENTRY_IID(__uuidof(paddinLib::_ISiteDownEvents), IExt)
END_COM_MAP()

CComPtr<paddinLib::ISiteDown> m_spDown;
DWORD m_dwDownCookie;


// CPP
STDMETHODIMP CDown::Init()
{
    if (m_spDown == nullptr)
    {

        HRESULT h = CoCreateInstance(
            paddinLib::CLSID_SiteDown, NULL, CLSCTX_ALL,
            paddinLib::IID_ISiteDown, reinterpret_cast<LPVOID*>(&m_spDown));
        if (SUCCEEDED(h) && m_spDown)
        {
            h = AtlAdvise(m_spDown, GetUnknown(), paddinLib::DIID__ISiteDownEvents, &m_dwDownCookie);
        }
    }

    return S_OK;
}

Answer 2

I did a snippet for you. These are two huge add-ins with multiple com components. The key is that when I fire an event from add-in #1 it acts as if there are no connections that were successfully made in add-in #2.

Answer 3

I have done tons of these com components. I can definitely tell you it has something to do with Outlook. I will get to the bottom of this and I will let you know what the issue is.