When MEF meets Silverlight

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When MEF meets SilverlightAmr Elsehemy

amr.elsehemy@me.com

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Speaker

• TA at Faculty of Information and Computer Science Ain Shams University

• Senior Software Engineer at ITWorx

• MCSD, MCPD + more.

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What's MEF?

• The Managed Extensibility Framework– “The Managed Extensibility Framework (MEF)

is a new library in .NET 4 / Silverlight 4 for building applications that can be incrementally extended” – mef team

– “An extensible framework for composing applications from a set of loosely-couple parts discovered and evolving at run-time” – mtaulty

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Why was MEF built?

App

Add B

Put the D

Can I have C

I need A

Then get me E

F

G

A

C

B

GD

EF

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Why MEF

• For customers• For you and your team • Always there, always ready

– In the framework!

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MEF Basics…

An Application is built of parts

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DemoBuilding our thing

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3 Magic steps

• Export it

• Import it

• Compose it

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Export it

[Export(typeof(IThing))]public class Thing{}

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ExportIThing

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Import it

public class MainPage{ [Import(typeof(IThing))] public IThing thing;}

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IThing

Import

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Compose it

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public class MainPage{public MainPage(){

CompositionInitializer.SatisfyImports(this);}

Compose

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DemoGiving more

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Import it - Metadata

ImportMany

[ImportMany]public IEnumerable<Lazy<IThing,

IThingMetadata>> somethings;

IThing

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Export it - Metadata

Put me in the

left

Export

[ExportMetadata("Position", ThingPosition.Left)][Export(typeof(IThing))]public partial class Thing{}

IThing

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Customize it – Custom exports

[ThingExport(Position = ThingPosition.Left)] public class Thing{}

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Put me in the

left

ExportIThing

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DemoExploring the catalogs

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AggregateCatalog

AssemblyCatalog

TypeCatalog

Compose it – Catalogs

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DemoTrim your apps break up your xaps

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Recomopose - DeploymentCatalog

• Recomposition is key in Silverlight apps– Initial download, small in size.– Download more functionality.

• A special Silverlight catalog DeploymentCatalog.

• Trace changes with IPartImportsSatisfiedNotification

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MEF versions

• .NET Framework shipping with Silverlight4• .NET Framework 4 shipping with VS 2010• Silverlight 3 & .NET Framework V3.5 SP1

– Source on Codeplex (MSPL)

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Resources

• silverlight.net• mef.codeplex.com• mefcontrib.codeplex.com• blogs.msdn.com/gblock• mtaulty.com – He is awesome!

– channel9.msdn.com/tags/learnMEFSL4

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Questions?

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Thank you

• Contacts amr.elsehemy@me.com twitter @amrelsehemy Blog

http://amrelsehemy.net