Re: COM beginner - 2 apps using the same instance of a component.

From: xtreem (invalid_at_hotmail.com)
Date: 09/18/04

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    Date: Sun, 19 Sep 2004 00:10:15 +1000

    "xtreem" <invalid@hotmail.com> wrote in message
    news:414c01a8$0$19428$61c65585@uq-127creek-reader-01.brisbane.pipenetworks.com.au...
    > "Igor Tandetnik" <itandetnik@mvps.org> wrote in message
    > news:%23j62NPMnEHA.3172@TK2MSFTNGP10.phx.gbl...
    >> "Eric" <eric_boissard@hotmail.com> wrote in message
    >> news:d9a55bc6.0409170633.47637859@posting.google.com
    >>> I am trying to learn COM at the moment. I have managed to write a
    >>> simple COM component in a dll. I can create one instance of this
    >>> component in a simple app. What I would like to do noe, is to create a
    >>> second app that uses the same instance of this object.
    >>
    >> Bad idea. If you want that, you should have created an out-of-proc
    >> component in the first place (the one implemented in an EXE rather than
    >> a DLL).
    >
    > Id also like to do something similar. The reason I have originally made it
    > an in-proc dll server is because that is how it is used most of the time,
    > but I would like to expose it as well.
    >
    > It is a automation object in a .dll which is loaded by a host .exe as a
    > plugin. I am using the automation object to control various aspects of the
    > application, through scripts that run in-process and eventually by other
    > processes which obtain this object.
    >
    > I realise I could make an out of proc server exe project and just make it
    > into a .dll, but Id prefer to keep it how it is if possible.
    >
    > I would prefer not to touch the registry for this project, I had intended
    > on just calling CoRegisterClass with a custom IClassFactory which just
    > returns my object. External apps would get my object through 'GetObject'
    > type of calls with the GUID, rather than 'CreateObject' with a prog id.
    >
    > Would this work ok? What are the significant differences between a .dll
    > and .exe ATL project? Keeping in mind I will be avoiding registering stuff
    > in the registry.
    >

    I managed to figure it out, the following two lines pretty did the trick,
    plus putting DECLASE_CLASS_FACTORY_SINGLETON in the application object.

    HRESULT hr = CoRegisterClassObject(CLSID_Application,
    (IUnknown*)pApplication->GetUnknown(), CLSCTX_LOCAL_SERVER,
    REGCLS_MULTIPLEUSE, &dwr);

    hr = RegisterActiveObject(pApplication->GetUnknown(), CLSID_Application,
    ACTIVEOBJECT_WEAK, &dwr2);

    Its probably not perfect, but I'll fine tune it over time.

  • Next message: Hawk: "Re: Did MS changed some interface methods in Outlook View Control"

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