This document outlines a 12 step program for becoming addicted to the Managed Extensibility Framework (MEF). MEF is a framework for building extensible applications and components. The steps include admitting your addiction, learning where to find MEF code and documentation, understanding how MEF handles imports and exports, observing further use cases, and sharing experiences and continuing your education about MEF.

1. Getting Addicted to MEF A 12 Step Program To Become Addicted to Awesomeness

2. Step 1: Admitting James Eggers From Kansas City Addicted for about a Year Talk about it on Twitter and my blog. Find Odd Situations to Use It More.

3. MEF? Managed Extensibility Framework A framework to simplify building internally and externally compose-able applications Could possibly become the “LINQ” of .Net 4

4. Current Issues in Extensibility Limited Documentation Complex APIs Reflection Large Inheritance Chains Difficult to Estimate

5. Step 2: Giving In Easy To Use Easy To Learn Auto-Composition Metadata Custom Contracts Open Source Auto-Discovery Extensible

6. Step 3: Where to Find MEF Codeplex http://mef.codeplex.com .Net Framework 4

7. Step 4: Identifying Items

8. Step 5: Observing the Addition

9. Step 6: Understanding - Exports Extensions To Be Consumed Export & InheritedExport Attributes PartNotDiscoverable Attr. Different Objects: Properties Methods Classes

10. Step 6: Understanding - Imports Consumers Extensibility Points Import Attribute ImportMany Attribute Different Objects: Properties Fields Constructor Params

11. Step 6: Understanding - Catalogs Discovers and Instantiates Exports Used by Containers Multiple Types TypeCatalog AssemblyCatalog DirectoryCatalog AggregateCatalog

12. Step 7: Observing Further

13. Step 8: Sharing Information Metadata Used to provide extra information Lazy Instantiation ExportMetadata Attr. Demo

14. Step 9: Sharing Experiences Lessons Learned InheritedExport can cause hide metadata ImportMany to IList<T> has to be instantiated before composition PartNotDiscoverable Attribute doesn't work with TypeCatalogs

15. Step 9: Sharing Experiences Lessons Learned(cont) Stable Composition Can Lead to a lot of Drinking Debugging. Directory Catalog can load multiples if 2 assemblies are found with the same type in said directory. Directory Catalog does not look at child directories. GetCallingAssembly() is great for unit testing part imports.

16. Step 10: Identifying Opportunities IoC Container MVC Controller Factory “ Flashcard” style programs Rules Engines App Themes Workflow Steps Many More

17. Step 11: Practical Observation

18. Step 12: Continuing Education Codeplex - http://mef.codeplex.com MSDN - http://msdn.microsoft.com My Blog - http://RandomActsOfCoding.Blogspot.Com MEF Contrib - http://mefcontrib.codeplex.com

19. My Information James Eggers Email - [email_address] Blog - http://RandomActsOfCoding.Blogspot.Com Twitter - @JamesEggers