Question

In my bootstrapper:

namespace Conduit.Mam.ClientServices.Common.Initizliaer
{
    public static class Initializer
    {
        private static bool isInitialize;
        private static readonly object LockObj = new object();
        private static IUnityContainer defaultContainer = new UnityContainer();

        static Initializer()
        {
            Initialize();
        }

        public static void Initialize()
        {
            if (isInitialize)
                return;

            lock (LockObj)
            {
                IUnityContainer container = defaultContainer;

                //registering Unity for MVC
                DependencyResolver.SetResolver(new UnityDependencyResolver(container));

                //registering Unity for web API
                //  GlobalConfiguration.Configuration.DependencyResolver = new Unity.WebApi.UnityDependencyResolver(container);

                #region managers
                container.RegisterType<ISettingsManager, SettingsManager>();

                container.RegisterType<IMamDataManager, MamDataManager>();

                container.RegisterType<IAppsDataManager, AppsDataManager>();
                #endregion

                if (!isInitialize)
                {
                    isInitialize = true;
                }
            }
        }
    }
}

in my controller’s code:

ISettingsManager sm = mUnityContainer.Resolve<ISettingsManager>();

hovering on mUnityContainer I see ISettingsManager is mapped to SettingsManager

but then I get the error:

Exception is: InvalidOperationException – The current type, is an
interface and cannot be constructed. Are you missing a type mapping?

I have also tried

ISettingsManager sm = (ISettingsManager)mUnityContainer.Resolve<>(typeof(ISettingsManager));

but no use

Answer 1

You are incorrectly using Dependency Injection. The proper way is to have your controllers take the dependencies they need and leave to the dependency injection framework inject the concrete instances:

public class HomeController: Controller
{
    private readonly ISettingsManager settingsManager;
    public HomeController(ISettingsManager settingsManager)
    {
        this.settingsManager = settingsManager;
    }

    public ActionResult Index()
    {
        // you could use the this.settingsManager here
    }
}

As you can see in this example the controller doesn’t know anything about the container. And that’s how it should be.

All the DI wiring should happen in your Bootstraper. You should never use container.Resolve<> calls in your code.

As far as your error is concerned, probably the mUnityContainer you are using inside your controller is not the same instance as the one constructed in your Bootstraper. But since you shouldn’t be using any container code in your controllers, this shouldn’t be a problem anymore.