Sending phone notifications to desktop work because there is a simple framework for the phones, and all your app as to do is listen for that event and echo the message to the desktop.
The reverse is significantly harder because there is simply no unified notification framework yet. Every app handles notifications differently. I haven't written desktop apps for windows at that depths, but notice how most application icons on the taskbar light up when there's an event? (May not always be a valid notification). Well, my first guess is that you'd have to write a listener for that - assuming you're given that kind of access in the OS in the first place. [ Check out this SO answer ].
Once you have a listener in place, you can know when an app receives a notification. However, unless the app exposes a method to see what the notification is though the taskbar, it is unlikely that you can derive the contents ...