asp.net mvc - Import aspect is not working using MEF -

using mefcontrib.mvc3 on mvc web application. used following class initialize mef before application start event. class auto generated(downloaded) nuget. tiny changes applied catalog(for plugins folder) , controller factory segments.

[assembly: webactivator.preapplicationstartmethod(typeof(omr.cms.app_start.mefcontribmvc3), "start")]  namespace omr.cms.app_start {     using system.componentmodel.composition.hosting;     using system.linq;     using system.web.mvc;     using mefcontrib.hosting.conventions;     using mefcontrib.web.mvc;      public static class mefcontribmvc3     {         public static void start()         {             // register compositioncontainerlifetimehttpmodule httpmodule.             // makes sure cleaned correctly after each request.             compositioncontainerlifetimehttpmodule.register();              // create mef catalog based on contents of ~/bin.             //             // note class in referenced assemblies implementing in "icontroller"             // automatically exported mef. there no need explicit [export] attributes             // on asp.net mvc controllers. when implementing multiple constructors ensure             // there 1 constructor marked [importingconstructor] attribute.             var catalog = new aggregatecatalog(                 //new directorycatalog("bin"),                 new directorycatalog("plugins"),                 new conventioncatalog(new mvcapplicationregistry())); // note: add own (convention)catalogs here if needed.              // tell mvc3 use mef dependency resolver.             var dependencyresolver = new compositiondependencyresolver(catalog);             dependencyresolver.setresolver(dependencyresolver);              // tell mvc3 resolve dependencies in controllers             controllerbuilder.current.setcontrollerfactory(new mymefcontrollerfactory(dependencyresolver));              // tell mvc3 resolve dependencies in filters             filterproviders.providers.remove(filterproviders.providers.single(f => f filterattributefilterprovider));             filterproviders.providers.add(new compositionfilterattributefilterprovider(dependencyresolver));              // tell mvc3 resolve dependencies in model validators             modelvalidatorproviders.providers.remove(modelvalidatorproviders.providers.oftype<dataannotationsmodelvalidatorprovider>().single());             modelvalidatorproviders.providers.add(                 new compositiondataannotationsmodelvalidatorprovider(dependencyresolver));              // tell mvc3 resolve model binders through mef. note model binder should decorated             // [modelbinderexport].             modelbinderproviders.binderproviders.add(                 new compositionmodelbinderprovider(dependencyresolver));         }     } } 

and using followin code on application class:

using omr.core.web.filters; using omr.core.web.routing; using system; using system.collections.generic; using system.componentmodel.composition; using system.web.mvc; using system.web.optimization; using system.web.routing;  namespace omr.cms {     public class mvcapplication : system.web.httpapplication     {         [importmany(typeof(ifilterregistration))]         public ienumerable<lazy<ifilterregistration>> filters { get; set; }          protected void application_start()         {             arearegistration.registerallareas();              bundleconfig.registerbundles(bundletable.bundles);              registerfilters();             registerroutes();         }          private void registerfilters()         {             var filters = globalfilters.filters;             var filterregistrations = dependencyresolver.current.getservices<ifilterregistration>();              foreach (var registar in filterregistrations)                 registar.register(filters);         }          public void registerroutes()         {             var routes = routetable.routes;             var routeregistrations = dependencyresolver.current.getservices<irouteregistration>();              // ignores             foreach (var registrar in routeregistrations)                 registrar.ignore(routes);              // routes             foreach (var registrar in routeregistrations)                 registrar.route(routes);         }     } } 

the problem following property null on application start method.

importmany(typeof(ifilterregistration))] public ienumerable<lazy<ifilterregistration>> filters { get; set; } 

but following lines working:

var filterregistrations = dependencyresolver.current.getservices<ifilterregistration>(); 

why import declaration isn't work?