If you are an Objective-C developer, you are well on your way to leveraging your skills and existing Objective-C code on the Xamarin platform, while reaping the code reuse benefits of C#. This section serves as an entry point to Xamarin.iOS, and points to a wealth of information about using existing Objective-C code from C#.
Xamarin offers a path for developers targeting iOS to move their non-user interface code to platform agnostic C# so that it can be used anywhere C# is available, including Android via Xamarin.Android and the various flavors of Windows. However, just because you use C# with Xamarin doesn't mean you can't leverage existing skills and Objective-C code. In fact, knowing Objective-C makes you a better Xamarin.iOS developer because Xamarin exposes all the native iOS and OS X platform APIs you know and love, such as UIKit, Core Animation, Core Foundation and Core Graphics to name a few. At the same time, you get the power of the C# language, including features like LINQ and Generics, as well as rich .NET base class libraries to use in your native applications.
Additionally, Xamarin allows you to leverage existing Objective-C assets via a technology know as bindings. You simply create a static library in Objective-C and expose it to C# via a binding, as illustrated in the following diagram:
This doesn't need to be limited to non-UI code. Bindings can expose user interface code developed in Objective-C as well.
Transitioning from Objective-C
You'll find a plethora of information on our documentation site to help ease the tranistion to Xamarin, showing how to integrate C# code with what you already know. Some highlights to get you started include:
- C# Primer for Objective-C Developers - A short primer for Objective-C developers looking to move to Xamarin and the C# language.
- Walkthrough: Binding an Objective-C Library - A step-by-step walkthrough for reusing existing Objective-C code in a Xamarin.iOS application.
Once you have a grasp of how C# compares to Objective-C and have worked through the binding walkthrough above, you'll be in good shape for tranistioning to the Xamarin platform. As a follow up, more detailed information on Xamarin.iOS binding technologies, including a comprehensive binding reference is available in the Binding Objective-C section.
Finally, after moving to Xamarin.iOS, you'll want to check out the cross-platform guidance we have, including case studies of reference applications we have devleoped, along with best practices for creating reusable, cross-platform code contained in the Building Cross Platform Applications section.