Re: Remoting and Windows messages (e.g., PlugNPlay message)

Thanks for the reply. Sorry if this is the wrong forum. I
saw
"DotNetDevelopment" and ".NET Remoting"
and thought this was the right
place. If there's somewhere more appropriate (that isn't
dead, of
course), please let me know. If worst comes to worst, I can
re-work it
in C#, but I don't think the problem is C++-specific. (I
used C++
because that's what my real project's code is in.)

My understanding, which could be flawed, is that on Windows,
when such
a PnP event occurs, a Windows message is broadcast to all
apps.
Indeed, if I make a CLR or standard C++ console app, which
by default
has no message pump, I get the same effect as with Remoting
-- namely,
no callback -- whereas if I make a simple MFC or WinForms
app, which
does have a message pump, I get the callback. The difference
seems
tied to Remoting somehow.

If my understanding of how the PnP messaging works is
correct, then
the client and server, each of which have a WinForms GUI and
hence a
message pump, should get the PnP message independently and
handle it
appropriately. I have not, however, determined if either the
client or
server receives such a Windows message, though I presume
that at least
the server has not received it since I see no callback. How
can I
check for sure? Is it possible that the client is receiving
the
message but the server isn't *because* they are connected
via Remoting
(seems strange since they're separate processes that are
started
independently)?

What "remoting configuration" information are you
looking for?

Cheers! --M

PS, Sorry if this shows up twice. Google is giving me
problems
tonight.

On Feb 23, 9:37 am, "Andrew Badera" <and...badera.us> wrote:
> You say the problem comes when you introduce remoting,
but then you say your
> app apparently never gets any events. You'll need to be
a little clearer for
> us dumb non C++ folks (this is a C#/VB forum,
syntactically speaking) are
> you saying the client never fires an event, or your
remoting server never
> seems to be catching any events? if the latter, what's
your remoting
> configuration look like, on both ends?
>
> On 2/22/08, mlimber <mlim...gmail.com> wrote:
>
>
>
>
>
> > Hi,
>
> > I have a third-party DLL over which I have no
control. I supply it a
> > delegate/callback function to be invoked when some
event occurs (in my
> > case, a USB device is added to or removed from the
system). I have
> > several applications that use this DLL and its
event processing
> > successfully, including an MFC app and a WinForms
app.
>
> > The problem comes in when I introduce .NET
Remoting. I've reduced the
> > code a bit for simplicity, but here is the class
that I export:
>
> >   /////////////////////////////////////////
> >   // Remoting Library.h
> >   /////////////////////////////////////////
>
> >   #include "../USBTargetImpl.cpp"
>
> >   namespace RemotingLibrary
> >   {
> >     public ref class SampleObject : public
System::MarshalByRefObject
> >     {
> >     public:
> >         SampleObject();
> >         System::Boolean m_isDevicePresent;
> >     private:
> >         USBTargetImpl^  m_usb;
> >     };
> >   }
>
> >   /////////////////////////////////////////
> >   // Remoting Library.cpp
> >   /////////////////////////////////////////
>
> >   #include "Remoting Library.h"
> >   #include <vcclr.h>
>
> >   namespace
> >   {
> >     gcroot<RemotingLibrary::SampleObject^>
s_sampleObject;
>
> >     void USBCallback( const bool isDevicePresent
)
> >     {
> >         if( s_sampleObject )
> >         {
> >             s_sampleObject->m_isDevicePresent =
isDevicePresent;
> >         }
> >     }
> >   }
>
> >   RemotingLibrary::SampleObject::SampleObject()
> >     : m_usb( gcnew USBTargetImpl( &USBCallback
) )
> >     , m_isDevicePresent( true )
> >   {
> >     s_sampleObject = this;
> >   }
>
> >   //////////////////////////////////////////////
>
> > As you can see, I supply a callback to a member in
the constructor to
> > RemotingLibrary::SampleObject. The code for
USBTargetImpl is not
> > important for our purposes here, but I can post it
if you think you
> > need to see it (it registers its own internal
callback with the third-
> > party DLL and, on add/remove events, calls back
the function supplied
> > to the constructor when its callback gets
invoked).
>
> > My server and client code for this simplified
example are converted to
> > Managed C++ and adapted from <http://www.develo
per.com/net/cplus/
> > article.php/1479761>. In particular I made the
client and server
> > WinForms apps rather than console apps (but the
console apps don't
> > work either, presumably since there is no message
pump). The client
> > just polls the m_isDevicePresent variable every
half-second or so.
>
> > The problem is, my app apparently never gets any
add/remove events and
> > hence the callback is never invoked. My
supposition is that the
> > Windows message for PlugNPlay is not being handled
in a normal way in
> > the server because of Remoting.
>
> > Any thoughts on how to handle this better?
>
> > Thanks in advance! --M
>
> --
> --Andy Baderahttp://andrew.badera.us/

> and...badera.us
> (518) 641-1280
> Google me:http://w
ww.google.com/search?q=andrew+badera

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