Question

Initial deployment of the site works fine. After about 2-3 hours, the controllers suddenly cannot be instantiated due to a dependency cannot be resolved (or at least that’s what the error message tells me).

I have tried various things, but none of which seem to resolve it. Does anyone have any ideas what I can check?

Answer 1

i still have no idea what was happening, but i managed to fix it. i was using a third-party bootstrapping library to register my components and mappings. but after rolling my own with MEF, and controlling the registrations myself, the issue went away. i’m guessing it was doing something funky by disposing things when it shouldn’t have. thanks for the help.

In case someone encounters this problem using http://bootstrapper.codeplex.com/ with the following declaration:

    Bootstrap.Bootstrapper
        .With.Unity()
        .And.AutoMapper()
        .And.ServiceLocator()
        .Start();

I replaced that with:

    IUnityContainer container = new UnityContainer();
    MEFContainer mefContainer = new MEFContainer();
    mefContainer.UnityRegistry.ForEach(x => x.Register(container));
    container.RegisterInstance<IMappingEngine>(Mapper.Engine);
    mefContainer.AutoMapperRegistry.ForEach(x => x.CreateMap(Mapper.Configuration));

where

    private class MEFContainer
    {
        [ImportMany(typeof(IUnityRegistration))]
        public List<IUnityRegistration> UnityRegistry { get; set; }

        [ImportMany(typeof(IMapCreator))]
        public List<IMapCreator> AutoMapperRegistry { get; set; }

        public MEFContainer()
        {
            var catalog = new DirectoryCatalog("bin");
            var compositionContainer = new CompositionContainer(catalog);
            compositionContainer.ComposeParts(this);
        }
    }

Note that IUnityRegistration.Register() and IMapCreator.CreateMap() are defined in the third-party code. MEF references System.ComponentModel.Composition
and System.ComponentModel.Composition.Hosting. Will eventually refactor.