Best way to keep a .net client app updated with status of another application

Question

I have a Windows service that's running all the time, and takes some action every 15 minutes. I also have a client WinForms app that displays some information about what the service is doing. I'd like the forms application to keep itself updated with a recent status, but I'm not sure if polling every second is a good move performance-wise.

• When it starts, my Windows Service opens a WCF named pipe to receive queries (from my client form)
• Every second, a timer on the winform sends a query to the pipe, and then displays the results. If the pipe isn't there, the form displays that the service isn't running.

Is that the best way to do this? If my service opens the pipe when it starts, will it always stay open (until I close it or my service stops)? In addition to polling the service, maybe there's some way for the service to notify any watching applications of certain events, like starting and stopping processing? That way, I could poll less, since I'd presumably know about big events already, and would only be polling for progress.

Anything that I'm missing?

Answer 1

I would steer clear of polling if possible. You're much better off adopting an event-based mechanism, which reduces overhead and provides just-in-time status updates as necessary.

You're already ahead of the curve. WCF is definitely the way to go here for .NET-based applications. And since your form and service are on the same system, the named pipe binding is the one to use as well. Now all you need is to have your service publish events, including periodic status updates, that your form can listen to when it's open.

The easiest way I've found to do this is to use Juval Lowy's Publish-Subscribe Framework. The neat thing about this framework is that it decouples the publisher from the subscriber. The publisher publishes events, not caring if a subscriber is there or not. If a subscriber is present, the event is forwarded for its consumption. Based on your description, I think this would work very well for you.