Re: Handling DISPID_AMBIENT_DLCONTROL in IDispatch::Invoke

"Igor Tandetnik" <>
Sun, 27 May 2007 09:50:13 -0400
"herc" <> wrote in message

I am working on an ATL8 program that uses the WebBrowser control. I
need to implement the DISPID_AMBIENT_DLCONTROL ambient property but am
stumped at how to actually implement the IDispatch::Invoke(). I am
using the IAxWinAmbientDispatchEx interface from the CAxWindow control
and giving it my own custom implementation of IDispatch:

class CAmbientDispatch :
public CComObjectRootEx<CComSingleThreadModel>,
public IDispatch
   CAmbientDispatch() {}


You don't need an explicit IUnknown entry. IDispatch one is sufficient.
It's harmless though.

           DISPID dispIdMember,
           REFIID riid,
           LCID lcid,
           WORD wFlags,
           DISPPARAMS *pDispParams,
           VARIANT *pVarResult,
           EXCEPINFO *pExcepInfo,
           UINT *puArgErr)
       // Change user agent for this web browser host during
       if (dispIdMember == DISPID_AMBIENT_USERAGENT)
           return S_OK;


I am trying to set the user-agent, the question is, how exactly do I
do that? The pVarResult is NULL

Are you sure pVarResult is NULL? That would be most unusual. I find it
hard to believe, no offense intended. pVarResult is not supposed to be
NULL, and you are supposed to pack your return value into it. Are you
sure you are not looking at the contents of pVarResult variant, but at
pVarResult pointer itself?
With best wishes,
    Igor Tandetnik

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