Re: COM Interface intialization

From:

"Brian Muth" <bmuth@mvps.org>

Newsgroups:

microsoft.public.vc.atl

Date:

Mon, 15 Jan 2007 11:21:08 -0800

Message-ID:

<e5RPQpNOHHA.448@TK2MSFTNGP04.phx.gbl>

"Steven Edison" <EdisonCPP@newsgroups.nospam> wrote in message
news:%23XYleLNOHHA.4604@TK2MSFTNGP06.phx.gbl...

This is probably a very simple question.
And I feel like I should know this... but....
(And I hope this is okay under ATL group.)

If I have an interface implementation like this:

CItemInfo: public CComCoClass<CItemInfo, &CLSID_ItemInfo>
{
....
    STDMETHOD(get_SomeData)(LONG* pVal); //prop
    void SetSomeData(LONG nVal); //unexposed function
   //other methods and props....
...
};

All the interface properties are read (get) only.

What I'd like to do is something like this:

STDMETHODIMP CAnotherInterfaceImpl::GetItemInfo(IUnknwn** pUnk)
{
    CItemInfo* pInfo = new CItemInfo; //above impl class
    pInfo->SetSomeData(0x42); *pUnk = (IUnknown*)pInfo;
    return S_OK;
}

The usual paradigm is something like this:

STDMETHODIMP CAnotherInterfaceImpl::GetItemInfo(IUnknwn** pUnk)
{
    CComObject<CItemInfo> *pInfo;
    pInfo = CComObject<CItemInfo>::CreateInstance (&pInfo);
    pInfo->SetSomeData(0x42);
    pInfo->AddRef(); // bring reference count up to one
    *pUnk = pInfo->GetUnknown ();
    return S_OK;
}

Brian