Comment Feed for Channel 9 - Silverlight TV Episode 5: Using Metadata with MEF http://ecn.channel9.msdn.com/o9/previewImages/100/523691_100x75.jpg Channel 9 - Silverlight TV Episode 5: Using Metadata with MEF Hamilton Verissimo, Program Manager working on MEF, makes a return visit to Silverlight TV to follow up his discussion of MEF. This time Hamilton discusses different ways metadata can be used with MEF and suggests some pros and cons for each. As usual, he dives right into the code samples and gives some great guidance on MEF. Follow @SilverlightTV on Twitter for the latest updates. en Thu, 20 Jun 2013 08:10:13 GMT Thu, 20 Jun 2013 08:10:13 GMT Rev9 Re: Silverlight TV Episode 5: Using Metadata with MEF Very helpful distillation of the stages of declaring and consuming Export MetaData.  Thanks!

As a quick-start reference, any chance your could post those 4 sample cs files?

 

Gracias!

posted by philcockfield

]]> http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634005743070000000 Sun, 31 Jan 2010 22:38:27 GMT http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634005743070000000 philcockfield Re: Silverlight TV Episode 5: Using Metadata with MEF I have to watch this video because the guy on the left looks like Dwight Shrute.

posted by justncase80

]]> http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634006450680000000 Mon, 01 Feb 2010 18:17:48 GMT http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634006450680000000 justncase80 Re: Silverlight TV Episode 5: Using Metadata with MEF Excellent work...  MEF looks amazing...

posted by mgraham

]]> http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634006527100000000 Mon, 01 Feb 2010 20:25:10 GMT http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634006527100000000 mgraham Re: Silverlight TV Episode 5: Using Metadata with MEF I love the pace of the videos and the walk throughs. I do enjoy screen casts, but some can be painful to watch because of their speed.

 

I do have one request:

I reliase that I will get no sypathy for this, but I usually watch screen casts on full screen and I have a 27" monitor, when doing this, the video of the visual studio screens is very poor. Can you not move to using Smooth Streaming and HD?

 

Cheers

posted by Dewy

]]> http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634007320390000000 Tue, 02 Feb 2010 18:27:19 GMT http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634007320390000000 Dewy Re: Silverlight TV Episode 5: Using Metadata with MEF Dewy - We (Channel 9) are working on some changes to help make the entire experience even better. Unfortunately this does not help you right now, but we are looking into some improvements.

 

Thanks for watching!

posted by jopapa

]]> http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634007324790000000 Tue, 02 Feb 2010 18:34:39 GMT http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634007324790000000 jopapa Re: Silverlight TV Episode 5: Using Metadata with MEF Why do you need to write any code at all to filter on metadata?  Why not have an 'ImportMetadataAttribute' that causes MEF to do the filtering for me?  The most common case is an 'equals' match against the metadata key/values, I would think there would be a simple way to do this without all this Lazy buisness..  Something like this:

[Import]
[ImportMetadata("IsSecure", true)]
public IEmailSender Sender {get; set; }

 

or

 

[ImportMany]
[ImportMetadata("IsSecure", true)]
public IEnumerable<IEmailSender> Senders {get; set; }


It would also be nice to say 'I only want one, and I dont care which one' using an 'ImportAnyAttribute'.

posted by brandf

]]> http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634008134470000000 Wed, 03 Feb 2010 17:04:07 GMT http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634008134470000000 brandf Re: Silverlight TV Episode 5: Using Metadata with MEF Hi

The reason we didnt do this is because it's easy to get caught on complicated situations. What would happen if you want to build an expression (X) AND (Y) OR (W)? What's the semantic when more than one attribute is present (OR or AND)? and this kind of things. Hence imperative code would be prefered.

 

Thanks for the feedback

posted by haveriss

]]> http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634008291190000000 Wed, 03 Feb 2010 21:25:19 GMT http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634008291190000000 haveriss Re: Silverlight TV Episode 5: Using Metadata with MEF I'm not suggesting you remove the imperative way to handle these more complicated cases.  I just seems like overkill for what I would imagine is the common case.

It would be intersting to look at how Export Metadata is used in VS 2010 as a case study for how common these more complicated cases are.  My gut feeling is that equality comparison on a single piece of metadata (or AND'ed for multiple ImportMetadatas) is the common case.

This would make it more pay-for-play...

posted by brandf

]]> http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634008528600000000 Thu, 04 Feb 2010 04:01:00 GMT http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634008528600000000 brandf Re: Silverlight TV Episode 5: Using Metadata with MEF Hi Brandf


Thanks for the feedback. We've been looking into ideas such as ImportMetadata for a while and are exploring several options. One alternative approach to having it on the import side is to have an adapter part which sits in the middle and provides the filtering the importer needs without requiring the importer to know. A different approach is to have a custom collection (which MEF supports) which does the adaptation. That you can do today, for example: http://codepaste.net/ktdgoh

Regardless, we appreciate the feedback and are looking into better ways to handle this problem going forward.

 

posted by gblock

]]> http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634019142850000000 Tue, 16 Feb 2010 10:51:25 GMT http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634019142850000000 gblock Re: Silverlight TV Episode 5: Using Metadata with MEF Has the code for this episode been published anywhere?  There seems to be some very good stuff that I'd like to get my hands on!

posted by mgbecker

]]> http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634021860540000000 Fri, 19 Feb 2010 14:20:54 GMT http://channel9.msdn.com/Shows/SilverlightTV/Silverlight-TV-Episode-5-Using-Metadata-with-MEF#c634021860540000000 mgbecker