MVC3 & Ninject / Unity: Injecting a hierarchical service container

Question

I've been using Ninject for a while, but only for simple DI. I have a slightly more complex scenario that I'd like to cater for.

I'm using the Ninject.Web.MVC plugin with controller injection, which is forced on my a base controller, passed through to all of the inheriting controllers. Here's my basic pattern:

using System;
using System.Web;
using System.Web.Mvc;

using Business;

using Microsoft.Web.Infrastructure.DynamicModuleHelper;

using Ninject;
using Ninject.Web.Common;

namespace Web {

    #region Controller

    public class MyController : MyBaseController {
        public MyController(IMyService1 myService1, IMyService2 myService2)
            : base(myService1, myService2) {
        }
        public ActionResult MyAction() {
            MyServiceProp1.DoSomething();
            MyServiceProp2.DoSomethingElse();
            return View();
        }
    }

    public class MyBaseController : Controller {
        protected IMyService1 MyServiceProp1 { get; set; }
        protected IMyService2 MyServiceProp2 { get; set; }

        public MyBaseController(IMyService1 myService1, IMyService2 myService2) {
            MyServiceProp1 = myService1;
            MyServiceProp2 = myService2;
        }
    }

    #endregion
}

namespace Business {

    #region Services

    public interface IMyService1 {
        void DoSomething();
    }

    public interface IMyService2 {
        void DoSomethingElse();
    }

    public class MyService1 : IMyService1 {
        public void DoSomething() {
        }
    }

    public class MyService2 : IMyService2 {
        public void DoSomethingElse() {
        }
    }

    #endregion
}

#region Ninject stuff

namespace Web.App_Start {
    public static class NinjectWebCommon {
        private static readonly Bootstrapper bootstrapper = new Bootstrapper();

        /// <summary>
        /// Starts the application
        /// </summary>
        public static void Start() {
            DynamicModuleUtility.RegisterModule(typeof(OnePerRequestHttpModule));
            DynamicModuleUtility.RegisterModule(typeof(NinjectHttpModule));
            bootstrapper.Initialize(CreateKernel);
        }

        /// <summary>
        /// Stops the application.
        /// </summary>
        public static void Stop() {
            bootstrapper.ShutDown();
        }

        /// <summary>
        /// Creates a kernel that will manage the application.
        /// </summary>
        /// <returns>The created kernel.</returns>
        private static IKernel CreateKernel() {
            var kernel = new StandardKernel();
            kernel.Bind<Func<IKernel>>().ToMethod(ctx => () => new Bootstrapper().Kernel);
            kernel.Bind<IHttpModule>().To<HttpApplicationInitializationHttpModule>();

            RegisterServices(kernel);
            return kernel;
        }

        /// <summary>
        /// Loads modules and services
        /// </summary>
        /// <param name="kernel">The kernel.</param>
        private static void RegisterServices(IKernel kernel) {
            kernel.Bind<IMyService1>().To<MyService1>();
            kernel.Bind<IMyService2>().To<MyService2>();
        }
    }
}

#endregion

As you can see, I have multiple services. If I want to add MyService3, I will have to modify every single controller that's implemented the base controller. Whilst this isn't a massive job as it stands, it will be when the project is larger...

What I would like to do is implement some kind of service container, which I will inject in to the base controller, and therefore all of the implementing controllers (and any subsequent classes):

namespace Web {

    #region Controller

    public class MyController : MyBaseController {
        public MyController(IMyServiceContainer container)
            : base(container) {
        }
        public ActionResult MyAction() {
            MyServiceProp1.DoSomething();
            MyServiceProp2.DoSomethingElse();
            return View();
        }
    }

    public interface IMyServiceContainer {
        IMyService1 MyServiceProp1 { get; set; }
        IMyService2 MyServiceProp2 { get; set; }
    }

    public class MyBaseController : Controller, IMyServiceContainer {
        public MyBaseController(IMyServiceContainer container) {
            MyServiceProp1 = container.MyServiceProp1;
            MyServiceProp2 = container.MyServiceProp2;
        }

        #region Implementation of IMyServiceContainer

        public IMyService1 MyServiceProp1 { get; set; }
        public IMyService2 MyServiceProp2 { get; set; }

        #endregion
    }

    #endregion
}

This way, if I need to add a global dependency, I won't have to change any of the controllers, just the base controller, which is much easier to maintain.

Is there a way to achieve this with Ninject (or even Unity, as I will be changing it over to that shortly), and does the pattern / method have a specific name that I've not yet heard?

Answer 1

public interface IMyServiceContainer 
{
    IMyService1 MyService1 { get; }
    IMyService2 MyService2 { get; }
    IMyService3 MyService3 { get; }
}

public class MyServiceContainer 
{
    public IMyService1 MyService1 { get; private set; }
    public IMyService2 MyService2 { get; private set; }
    public IMyService3 MyService3 { get; private set; }

    public MyServiceContainer(IMyService1 myService1, IMyService2 myService2, IMyService3 myService3)
    {
        MyService1 = myService1;
        MyService2 = myService2;
        MyService3 = myService3;
    }
}

and then your base controller:

public class MyBaseController : Controller 
{
    public MyBaseController(IMyServiceContainer container) 
    {
        Container = container;
    }

    protected IMyServiceContainer Container { get; private set; }
}

and then the derived controller:

public class MyController : MyBaseController 
{
    public MyController(IMyServiceContainer container) : base(container) 
    {
    }

    public ActionResult MyAction() 
    {
        Container.MyService1.DoSomething();
        Container.MyService2.DoSomethingElse();
        return View();
    }
}

and now all that's left is to configure NInject:

private static void RegisterServices(IKernel kernel) 
{
    kernel.Bind<IMyService1>().To<MyService1>();
    kernel.Bind<IMyService2>().To<MyService2>();
    kernel.Bind<IMyService3>().To<MyService3>();

    kernel.Bind<IMyServiceContainer>().To<MyServiceContainer>();
}