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DCOM Problem on the server (help!)

Posted on 2002-05-23
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Last Modified: 2010-05-02
I have the following problem:

- project created in VB 6.00, enterprise edition
- client server application using DCOM

Now, this is the problem: Whenever I have a problem on the network, my server hangs, and the application is not responding anymore to any command. I thinks that this is due to the fact that the client is sending some event to the remote server, which is unavailable. This hangs the clients, that is waiting for the ending of the call since the project is single-threaded.

The client is showing a form, so I can't just recompile the project as multi-threaded, since I would have a form for each instance of the client...

Please help me! Any suggestion?
I can increase point to 200.... :))

Thanks in advance...
Marco.
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Question by:marconovaro
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Expert Comment

by:ca_heckler
ID: 7044563
DCOM usually don't behave all that well over a unreliable network connection. I'm not sure you can work around that in VB, as all the ALT/COM fun stuff is hidden.

Have you considering using sockets for the communication? Off course you would have to rely only on simple data types or implement some marshalling on your own, but this way at least you are in the control, and its still all VB.

Thrust-me, it is not that difficult: write a little wrapper object and use it on both sides.
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Author Comment

by:marconovaro
ID: 7046374

Dear ca_heckler,

thanks for the reply. I actually implemented a little workaround to the problem by means of:

- an ActiveX EXE that is multithreaded, and implements the DCOM interface to the clients
- an ActiveX EXE that is single-threaded, and shows the form (I need this because this side is used to communicate on the serial line (!)

This SEEMS to work, because I can also disconnect the net cable, and the server continues working. I actually don't know if this will solve the problem, since I still have to test it on the "unrelaiable network"...
Nevertheless, thanks very much indeed for the answer: I was thinking to change the project to use sockets (avoiding DCOM, that is creating much more mess than help). The problem is that I'm using the same ActiveX EXE both on the server (with COM) an on some clients (with DCOM), so I should be able to use sockets also for the "local" communication.
I'll check how difficult it is for me to change the project itself.

Thanks again.
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