A week ago I concluded Microsoft Denmark’s 2010 .NET Community Christmas Calendar with a challenge about resolving closed types with MEF. As 2011 came around, the deadline ended, so it’s now time to pick the winner.

I didn’t get a lot of entries, which can be interpreted in at least one (or more) of the following ways:

• The challenge was too difficult
• The challenge wasn’t interesting
• The prize wasn’t attractive
• People had other things to do during the holidays

Whatever the reason, it made my task of picking a winner that much easier. The best Danish entry came from Daniel Volder Guarnieri who cheated a bit by partially hard-coding the composition of Mayonnaise into the ContainerBuilder. As I wrote in the original challenge, there are many ways to tackle the challenge, and one was to take the unit tests very literally :)

However, honorable mention must go to Boyan Mihaylov who participated just for the honor. He took a more general approach similar to Fluent MEF. This involves implementing a completely new ComposablePartCatalog with associated ComposablePartDefinition and ComposablePart implementations – not a trivial undertaking.

Kudos to Boyan and congratulations to Daniel. My thanks for your submissions, and a happy new year to all my readers!