The Visual Studio Editor and MEF

Although the MEF is a general-purpose extensibility framework applicable across a wide range of application scenarios, it is particularly applicable to extending the Visual Studio code editor for one simple reason: the editor itself was built by Microsoft using MEF. In other words, the code editor consists of a series of MEF parts. Adding additional parts to extend and change editor behavior is simply a matter of using the MEF design patterns and writing your own MEF parts to be discovered and used by the editor.

If you want to extend the editor, you need to know the exact editor extensibility points; in other words, you need to know which editor feature areas can be easily replaced or enhanced using your own MEF parts.

With our basic primer on MEF out of the way, it’s time to examine how to create an MEF-based project within Visual Studio and review the numerous extension points the editor exposes.