Xamarin enables developers to build mobile apps for Apple iOS (iPhone and iPad), Google Android, and Windows Mobile using C#. It is based on a third-party open source implementation of .NET known as Mono. Business logic layer can be written once and shared between all mobile platforms. User interface interactions and APIs are different on various mobile platforms, so the user experience layer is often custom for each platform.
Xamarin.Forms extends Xamarin to make cross-platform mobile development even easier by sharing most of the user experience layer, as well as the business logic layer.
Like Universal Windows Platform apps, Xamarin.Forms uses XAML to define the user interface once for all platforms using abstractions of platform-specific user interface components. Applications built with Xamarin.Forms draw the user interface using native platform widgets, so the app's look-and-feel fits naturally with the target mobile...