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POASP.NET MVC + MEF + MefContrib: Can't seem to get metadata from Exports
 

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  1. POASP.NET MVC + MEF + MefContrib: Can't seem to get metadata from Exports
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    <p>I'm using asp.net mvc3 with MEF + MEFContrib to load some services on my controllers. What's happening is that I can load the services - <code>IEnumerable&lt;IPublishService&gt; publishers</code> - with the <code>[ImportingConstructor]</code> but when I try to load the services with metadata - <code>Lazy&lt;IPublishService, IPluginMetaData&gt;[] publishers</code> - I get an empty array.</p> <p>Any thoughts on why? Thanks.</p> <p>My code:</p> <pre><code>public interface IPluginMetaData { string Name { get; } string Version { get; } } [MetadataAttribute] [AttributeUsage(AttributeTargets.Class, AllowMultiple = false)] public class PluginMetadataAttribute : ExportAttribute { public PluginMetadataAttribute(string name, string version) : base(typeof(IPluginMetaData)) { Name = name; Version = version; } public string Name { get; set; } public string Version { get; set; } } [Export(typeof(IPublishService))] [PluginMetadata("Default", "1.0.0.0")] public class SamplePublishService : IPublishService { } [ImportingConstructor] public HomeController(Lazy&lt;IPublishService, IPluginMetaData&gt;[] publisher /* Empty Array */ , IEnumerable&lt;IPublishService&gt; publishers /* Array with 1 service */) { } </code></pre> <p><strong>UPDATE (based on Daniel answer but still nothing)</strong></p> <pre><code>[MetadataAttribute] [AttributeUsage(AttributeTargets.Class, AllowMultiple = false)] public class PluginMetadataAttribute : ExportAttribute { public PluginMetadataAttribute(string name, string version) : base(typeof(IPublishService)) { Name = name; Version = version; } public string Name { get; set; } public string Version { get; set; } } [PluginMetadata("Default", "1.0.0.0")] public class GoogleSampleGroupPublishService : IPublishService { } [ImportingConstructor] public HomeController([ImportManyAttribute]Lazy&lt;IPublishService, IPluginMetaData&gt;[] publisher) { } </code></pre>
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