MEF & Silverlight 4 Beta - Part 2, Imports & Exports

Part 5 of a series of screencasts looking at the new Managed Extensibility Framework (MEF) in the Silverlight 4 beta.
MEF is a framework that simplifies the design of extensible applications and components. It can flexibly and dynamically discover a set of loosely coupled components and analyse their dependencies in order to compose them together at run time.
In this screencast, we look at an additional catalog in the Silverlight Toolkit Preview for Silverlight Beta 4, the PackageCatalog. This catalog adds the key ability of being able to download XAPs dynamically at runtime and ask MEF to discover and
compose the types contained within those XAPs into a pluggable application.
Tips for viewing:
I'm working to get together a Live Meeting in early 2010 with people from the MEF team in order that people can chat more about MEF in Silverlight. Stay tuned.
The next screencast in this series is
here.
Excellent screencasts,
Half way through the screencast I get a failure. Is it possible to fix this?
Is there some code we could download?
I am a newbie uisng MEF, what can we do with MEF that we cannot do with PRISM?
TIA
Yaz
Hi,
I've just played the video and, like you, I got a media failure at about 10 mins. I'm not sure what's causing this but, in the meantime I'd suggest a workaround using the "Downloads" drop down menu to download the HIGH WMV version, save it to your disk and watch it from there.
Ironically, that should be the same file that's appearing in the video player so I'm not sure how it works in one place and not the other but I'll see if I can get it resolved and will post here as/when that's done.
Thanks & sorry for the file problem,
Mike.
[I posted this question to your blog - but it didn't show up, so I'm not sure if it went into a moderator inbox, or the blog was broken. So, apologies if it got posted multiple times. Not *trying* to spam you].
Hi Mike. Thanks so much for these videos. You're a gifted communicator.
I had a question about this PackageCatlog video.
The way you structured the application was to divide it up into the various class libraries AND create corresponding Package (SL Apps) which were really just there to tie various configurations of DLL's together.
I was wondering if that was a hard-n-fast best practice? Would it also be sensible that if your application logic did cleave fairly readily around the XAP files, that you just create a set of SL-Apps (XAPs) and put the module's logic straight into that project (rather than seperate ClassLibrary assemblies)?
Many thanks!
Thanks Mike. I got your response over on your blog, here:
Why is better download XAP package ?
It is possible download single DLL files from web site, not XAP file ?