How to make a "push notification" service in Windows in C#, WPF?

Question

I have a WPF Browser application, written in C#. In which have a process where i need to notify users of its status. (i.e. notifying users when tasks are assigned to them).

The client doesn't want those notifications to be sent by mail, they want to have a tray icon that notifies each of the users when a "task" is assigned to them. however, this application is going to be used by a large group of users and by making a notification system based on polling the server for a status change, would imply wasting a lot of traffic, as they need the notification to be received by the user as close to "real time" as possible.

However, I could not find any examples of push notifications sent directly to any version of Windows.

To minimize bandwith used, I'd like to have an event listener on the server, and triggering the notifications from there, as it would just be one connection polling the server for changes.

How could I send the notifications from the server to each of the other users?

Answer 1

Assuming you're using WCF to communicate between client/server, consider duplex services: http://msdn.microsoft.com/en-us/library/cc645027(VS.95).aspx