I have an app using Xamarin.Forms targeting IOS, Android and WP 8.
I need push notification feature in my app.
I have seen the pushsharp
demos
This is not possible to do in pure Xamarin.Forms but is relatively trivial to implement a solution whereby they can be handled in the App.cs (although this will require platform specific implementations).
Take a look in the IXForms implementation within the Xamarin.Forms.Labs project where the notifications are channeled back to Forms project:
https://github.com/XLabs/Xamarin-Forms-Labs
and more specifically:
https://github.com/XLabs/Xamarin-Forms-Labs/tree/master/src/Platform/XLabs.Platform/Mvvm