In Unity, you normally use scripts to create functionality, but you can also include code created outside Unity in the form of a plug-in. You can use two different kinds of plug-in in Unity:
Managed code is accessible to the standard .NET tools that Unity uses to compile scripts. The only difference between managed plug-in code and Unity script code is that the plug-ins are compiled outside of Unity and so Unity might not be able to access the source. When using native plug-ins, Unity’s tools can’t access third-party code libraries in the same way that they can access the managed libraries. For example, if you forget to add a managed plug-in file to the project, you will get standard compiler error messages. Whereas, if you forget to add a native plug-in file to the project, you will only see an error report when you try to run the project.
The following pages explain how to create and use plug-ins in your Unity Projects:
MonoDevelop は 2018.1 以降 Visual Studio に置き換えられました