>Hi All,
>
>The application I'm currently working on needs to update all clients in real time. That is, if changes are made to any data these need to be broadcast to all clients. Does anyone know how to expose a client's method and how to call that method, bearing in mind the client could be located anywhere.
>
>I was hoping that COM would help me but the control seems to be in one direction, from client to server and not vice-versa.
>

You can register the "client" as an object with the "server" to give the server access to the clients methods. You don't need COM to do this. (Actually, COM introduces a few new issues...)

But you might be better off using a sort of mediator- a third object that knows about all objects that want to be notified when an event happens. That way, each object that can cause the event only neds to know about the mediator, and only needs to notify one party when he makes changes. The mediator is then responsible for notifying all of the other registered objects. Check out Steven Black's article on this at http://www.stevenblack.com/PTN-Mediator.ASP

>Also, I am reluctant to use timers.

Boy, me too.