Ninject Dependency Injection in ASP.NET MVC

Posted in ASP.NET MVC, ASP.NET, C#, Ninject, Dependency Injection, on 4/6/2014

About Ninject

Get Ninject Library

Last update is Sunday, January 4, 2015, looks like no one update/maintain it anymore...


Install-Package Ninject -Version 3.2.2

Interface

In C# for using Dependency Injection, you'll define your interface and class which will implement this interface. Once you defined interface and bind the relation via Ninject, then you could use this interface at other layer or same layer and without knowing what's the detail implementation about the specific interface.


namespace NinjectConstructorInjectionWeb
{
    public interface ISamurai
    {
        string GetData();
    }
}

Class


namespace NinjectConstructorInjectionWeb
{
    public class Samurai : ISamurai
    {
        public string GetData()
        {
            return "my data";
        }
    }
}

Dependency Resolve class in Ninject


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web.Mvc;
using Ninject.Syntax;
using Ninject;

namespace NinjectConstructorInjectionWeb
{
    public class NinjectDependencyResolver : IDependencyResolver
    {
        private readonly IResolutionRoot _resolutionRoot;

        public NinjectDependencyResolver(IResolutionRoot kernel)
        {
            _resolutionRoot = kernel;
        }

        public object GetService(Type serviceType)
        {
            return _resolutionRoot.TryGet(serviceType);
        }

        public IEnumerable GetServices(Type serviceType)
        {
            return _resolutionRoot.GetAll(serviceType);
        }
    }
}

Set up Ninject Dependency in application Global Class

By using Ninject, you could either setup binding as following, or setup binding as each module by inherict from NinjectModule class.


 protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();
            RegisterGlobalFilters(GlobalFilters.Filters);
            RegisterRoutes(RouteTable.Routes);


            // setting for Ninject
            IKernel kernel = new StandardKernel();

            kernel.Bind<ISamurai>().To<Samurai>();

            DependencyResolver.SetResolver(new NinjectDependencyResolver(kernel));
        }

Setup Ninject Dependency in Ninject Module


 public  class  MyModule  : NinjectModule 
     {
         public  override  void  Load()
         {
             Bind<ISamurai>().To<Samurai >()
                 .WithConstructorArgument("kernel" , this .Kernel);
         }
     }

Use Ninject Dependency in ASP.NET MVC Controller

The beauty of doing Depenency Injection in ASP.NET MVC controller is by passing the interface to the contructor of the MVC controller. User/Client don't need to know about the interface's logic.


private readonly ISamurai _samurai;
public HomeController(ISamurai samurai)
{      
    _samurai = samurai;
}

public ActionResult Test()
{
    // you should see "my data" here.
    ViewBag.Hi = _samurai.Attach();
    return View();
}

Unit test in Ninject + ASP.NET MVC App

Another important thing with Dependency Inject in Ninject is, UnitTest. Because everything is interface, you could setup different data at UnitTest to test your actual logic.


   [TestMethod ]
         public  void  Product()
         {
 			  ISamurai  testService = new  Samurai();
 
 			  HomeController  controller = new  HomeController (testService);
 
            controller.Product();
         }

Mocking data in Unit Test - Ninject + Moq

Use Ninject + Moq + Unit Test, so you can mock the temp data to the interface and pass to your controller.


   public  static  IProductBzService  GetProductService()
         {
             Mock  mock = new  Mock ();
             mock.SetupGet(x => x.Id).Returns(1);
             mock.SetupGet(x => x.Name).Returns("test name" );
             mock.SetupGet(x => x.Price).Returns(11.11m);
             mock.SetupGet(x => x.Unit).Returns(2);
             mock.Setup(x => x.Total()).Returns(999.999m);
 
             return  mock.Object;
         }

In conlusion

Ninject is cool C# .NET library for dependency injection, about couple years ago. looks like no one update it anymore, I would think this will be a legacy Denepencey Injection Library in the future.

What's my other choice for Dependency in .NET?

I would recommand use Autofac, it is well document, support different .NET library, such as ASP.NET Web Forms, MVC, WebAPI 1, WebAPI 2, Signal R, RIA, OWIN, WCF, MEF, NHibernate, Moq.

  1. Autofac
  2. Castle Windsor
  3. StructureMap
  4. Spring.NET
  5. Unity
  6. Puzzle.NFactory
  7. Ninject
  8. S2Container.NET
  9. PicoContainer.NET
  10. LinFu