Re: Trouble instantiatig callback object defined out-of-process

"Scott McPhillips [MVP]" <org-dot-mvps-at-scottmcp>
Sun, 10 Jun 2007 13:30:04 -0400
Igor Tandetnik wrote:

Don't derive ISink from IDispatch. Derive it from IUnknown, mark with
[oleautomation] attribute in IDL. Or else, make it a dispinterface and
use IDispEventImpl to implement it. It does not make sense to have a
dual interface for a callback.

Here's what I've done, but it does not build. Can you point out any
problems here? With my current state of knowledge I could be making a
dozen errors and never find the right magic combination. Are there any
published examples of doing this?

// .idl
    helpstring("IMySink Interface"),
interface IMySink : IUnknown {
    [id(1), helpstring("method Update")] HRESULT Update([in] BSTR bsUpdate);

// .h
class ATL_NO_VTABLE CMySink :
    public CComObjectRootEx<CComSingleThreadModel>,
    public CComCoClass<CMySink, &CLSID_MySink>,
    public IMySink

Result of trying to create it (in-process) is:
error C2664: 'ATL::CComObject<Base>::CreateInstance' : cannot convert
parameter 1 from 'CMySink **' to 'ATL::CComObject<Base> **'
1> with
1> [
1> Base=CMySink
1> ]

Scott McPhillips [MVP VC++]

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