Re: MSHTML IWebBrowser2 problem - Catching events causes missed keystrokes

Scot T Brennecke <>
Mon, 01 Jun 2009 23:52:43 -0500
<> wrote:

On May 30, 4:39 pm, "Scot T Brennecke" <>

Since this question relates to the use of MFC, why did you ask in the ATL newsgroup?

<> wrote in message
I've got a bit of a problem with my application using MSHTML.
Everything works except the odd keystroke gets missed typing fast. I
think it may have to do with sinking the events, like the system is
getting bogged down passing events around and then misses keyboard

The details: my application is a separate program written in C++ and
MFC in Visual Studio 2005. The program attaches to a currently running
(independent) instance of Internet Explorer, so the programs are in
two seperate processes/threads. My program gets a pointer to the
IWebBrowser2 interface of each tab and passes it to an corresponding
object of type CCmdTarget:

class CHandler : public CCmdTarget
  IWebBrowser2* m_pWebBrowser2;
  DWORD m_dwBrowserCookie;


This class keeps track of what's happening in the browser page. I sink
the browser events with the following command in CHandler:

LPUNKNOWN pUnkSink = GetIDispatch(FALSE);
retval = AfxConnectionAdvise((LPUNKNOWN)m_pWebBrowser2,
DIID_DWebBrowserEvents2, pUnkSink, FALSE, &m_dwBrowserCookie);

If I comment out the AfxConnectionAdvise, then no keystrokes are
missed but no more events are caught. If I leave the line in then I
correctly sink the events but miss the occasional keystroke if typing

Someone suggested marshalling may be the problem between the two
threads (mine and IE) but I'm not sure A) how to do that, and B) why
it would work _almost_ fine without it.

Any suggestions are greatly appreciated!

Sorry, wasn't sure where it fit best, had some suggest it had
something to do with AtlAdvise. I will look elsewhere for help..


I cross-posted my reply to you so that your question would appear in the
MFC newsgroup (where it is now). ATL has capabilities to do the things
your app does, but your app happens to use MFC instead. I was hoping
someone here might have a clue about your question. Perhaps there's
also a group that discusses browser app development.

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