In C# mobile development, design patterns are more important than ever. From MVC to MVVM. From Delegates to Protocols. Views and Controllers are central to mobile development and Models are as helpful as ever. We'll explore how to take advantage of this pattern-heavy development environment using Xamarin. From UI, data-binding, to services, we'll discuss built-in Android and iOS patterns as well as third-party frameworks such as MVVMCross and MVVM Light. The Gang of Four is in your phone and we will wield their power.