您可以实现SignalR。请参阅我的文档 - 使用SignalR的实时通知 - Docs.com [ ^ ]。

I have a web application where i want to implement notification system like facebook has in upper right corner notification button.
Anyway simple working example would be great to start with.

You can implement SignalR. Refer my doc - Real Time Notification using SignalR - Docs.com[^].