Glenn Block On MEF

I have some interesting in MEF for future projects. We are already using Unity for a dash of composite in on project, but there is so much more potential there than just that. It so happens that I’m as a Microsoft Conference today with Scott Guthrie, Jaime Rodriguez, and Glenn Block giving presentations.

I’m gonna live-blog this as he goes, so you may need to update this. Not time-stamping the updates though.

Fragments & points from Glenn’s talk:

• Phoenix is hot
• worked on Prism, Unity, and MEF (currently) [also working on View Model Infrastructure]
• not a comedian, not magician, not rock start.. just a guy who cares about maintainable software
• Extensibility
• Open-Closed Principle – open to be extended but closed to modifications
• Compose – composed, modular apps are a good thing, glossed over this so far..
• Where MEF is being used – Visual Studio Extensibility.. sample from VS2010 (oh why wont you install on win7 in vm fusion!)
• Really interesting demo in vs2010 popping up a regex dialog from intellisense. create new regex or use saved ones. way cool.
• Very cool demo of a came using MEF. Just opened a new dll while it was running to get a while new set of shapes. No reset.
• MEF basics
  • Export it
  • Import it
  • Compose it
• MEF is not type based. huh, i’m curious what he means. “not based on any types, but uses types for convenience” –glenn block
• Parts (components), Catalog (container - library of available parts). sounds like type registration to me. still not sure how it’s not type based.
• Compose it – type catalog, assembly catalog, directory catalog, aggregating catalog. this is starting to sound familiar: find and ways to load modules.
• showing how to create and register a rule. audience sample rule: IncrementByOneRule
• switching from manually registering types to AssemblyCatalog to find the types (rules in his sample) defined in his demo.
• Intersting, for demo which was only taking one rule, switched to [ImportMany] IEnumerable<IRule> {get;set} to accept a collection of rules instead of a single rule.
• But they are getting rid of [Export] in future release so the demo code is nearly obsolete. otherwise very cool
• [distracted by Ayende blog post. sry]
• Power of being declaritive. conventions, export. MEF just cares about contracts.
• lifetime management with MEF container (related, another)
• now showing a catalog form Ruby code. very very interesting. now MEF with XAML? impressive.
• I like how MEF is finding the click action for a button in the demo. not sure what I would do with my usual design as a result.

That is all. Nice intro and overview of MEF.

-j