What project type should I add as the "Core" project in a Xamarin solution?

Question

I started off my Xamarin project with an Android project. iOS and Windows Phone projects will come later. What I want now is a "Core" project (C#) for the business layer to be referenced by the Android project (and later shared with the others).

When I r-click the solution and select Add > New Project..., it defaults to my first choice of project for this solution:

I reckon I want either Visual C# > "Class Library" or "Portable Class Library" but need to know for certain before stepping into the void. Is the type of project I select definitely one or the other, or an "it depends" sort of thing?

Answer 1

If you intend to share it between multiple projects, then choose Portable Class Library.

http://docs.xamarin.com/guides/cross-platform/application_fundamentals/pcl/