Re: ATL Control as an event source and sink
For starters, I strongly suggest you ditch attributed ATL. There
are known bugs reported since 2002, and one of them is in
sinking events (a memory leak IIRC). Microsoft hasn't done
much with regards to fixing the issues (in fact their solution
was to disable attributed ATL by default in VC8).
Another point is, your COM object should _not_ be a sink as
well. This easily leads to circular reference counting and eternal
object lifetimes. You need to use a technique called split identity,
e.g. use a different object for sinking the events and forwarding
them to your COM object. An issue with the way IDispEventImpl
handles reference counting also requires you not derive from it
on your COM object, otherwise you get hidden circular reference
counting all over again. Implement your sink on a completely
separate C++ class derived from IDispEvent[Simple]Impl (if
your source interface is a dispinterface that is).
--
=====================================
Alexander Nickolov
Microsoft MVP [VC], MCSD
email: agnickolov@mvps.org
MVP VC FAQ: http://www.mvps.org/vcfaq
=====================================
"Sman" <sman@paradise.net.nz> wrote in message
news:eeedmf$rgo$1@news.freedom2surf.net...
Hi
I am trying to get an ATL single threaded dll to act as both an event
source
and sink by using both the event_source(com), event_receiver(com, true)
attributes.
Is this even possible?
I am trying to hook my dll to a singleton atl exe that I have created
using:
CComPtr<IServer> m_pIServer = 0;
m_pIServer.CoCreateInstance(__uuidof(CServer)); // this works
hr = __hook(_IServerEvents, m_pIServer); //but this returns a negative
long.
the exe server has an event HRESULT Transfer(VARIANT data); implimented
under _IServerEvents
I have also created a public function in my dll client called HRESULT
Transfer(VARIANT data); which should map to the server event but still the
client wont hook into the server.
Is there any sample code out there. I am finding it all very hard to
find.
Thanks in advance
Steve M