Mono 

Mono是一个由Novell公司（由Xamarin发起）主持的项目，并由Miguel de lcaza领导的，一个致力于开创.NET在Linux上使用的开源工程。它包含了一个C#语言的编译器，一个CLR的运行时，和一组类库，并实现了 ADO NET和ASP NET。与微软的.Net不同, Mono</a>项目不仅可以运行于Windows系统内,还可以运行于Linux, FreeBSD, Unix, Mac OS X和Solaris。

mobjc is a Mono library which allows .NET code to interoperate with Apple frameworks such as foundation and appkit. It makes it possible for managed code to call native Objective-C methods, native methods to call managed code, and new Objective-C classes to be defined in managed code. Exceptions are properly marshaled in both directions.

mobjc may be used by itself, but it's much nicer to use mcocoa which is built on top of mobjc and provides (mostly) type-safe wrappers for foundation and appkit.

mobjc requires Mac OS 10.5 or later.

mcocoa for their wrapper classes which allow Apple's Cocoa frameworks to be userd from Mono.