Ninject dependency injection with Asp.Net MVC3 or MVC4

Question

I am using Ninject MVC3 (version 3.0.0.0) for my ASP.Net MVC3 application installed using the NuGet package for dependency injection.

Here is the Global.asax change:

public class MvcApplication : NinjectHttpApplication { public static void RegisterGlobalFilters(GlobalFilterCollection filters) { filters.Add(new HandleErrorAttribute()); } public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.IgnoreRoute("favicon.ico"); routes.IgnoreRoute("{*favicon}", new { favicon = @"(.*/)?favicon.ico(/.*)?" }); routes.MapRoute( "Default", // Route name "{controller}/{action}/{id}", // URL with parameters new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults ); } protected override IKernel CreateKernel() { var kernel = new StandardKernel(); kernel.Bind<Func<IKernel>>().ToMethod(ctx => () => new Bootstrapper().Kernel); kernel.Bind<IHttpModule>().To<HttpApplicationInitializationHttpModule>(); RegisterServices(kernel); return kernel; } protected override void OnApplicationStarted() { base.OnApplicationStarted(); AreaRegistration.RegisterAllAreas(); RegisterGlobalFilters(GlobalFilters.Filters); RegisterRoutes(RouteTable.Routes); } /// <summary> /// Load your modules or register your services here! /// </summary> /// <param name="kernel">The kernel.</param> private static void RegisterServices(IKernel kernel) { kernel.Bind<IUserRepository>().To<UserRepository>(); kernel.Bind<IUserService>().To<UserService>(); kernel.Bind<ICommonRepository>().To<CommonRepository>(); kernel.Bind<ICommonService>().To<CommonService>(); } } 

But it gives the following error, although I have an inconspicuous constructor for my HomeController:

  System.NullReferenceException: Object reference not set to an instance of an object. Generated: Wed, 28 Mar 2012 05:49:01 GMT System.InvalidOperationException: An error occurred when trying to create a controller of type 'MVC3.Web.Controllers.HomeController'. Make sure that the controller has a parameterless public constructor. ---> System.NullReferenceException: Object reference not set to an instance of an object. at Ninject.Planning.Bindings.BindingConfiguration.GetProvider(IContext context) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Bindings\BindingConfiguration.cs:line 107 at Ninject.Planning.Bindings.Binding.GetProvider(IContext context) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Bindings\Binding.cs:line 212 at Ninject.Activation.Context.Resolve() in c:\Projects\Ninject\ninject\src\Ninject\Activation\Context.cs:line 157 at Ninject.KernelBase.<>c__DisplayClass10.<Resolve>b__c(IBinding binding) in c:\Projects\Ninject\ninject\src\Ninject\KernelBase.cs:line 386 at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext() at System.Linq.Enumerable.SingleOrDefault[TSource](IEnumerable`1 source) at Ninject.Planning.Targets.Target`1.GetValue(Type service, IContext parent) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Targets\Target.cs:line 197 at Ninject.Planning.Targets.Target`1.ResolveWithin(IContext parent) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Targets\Target.cs:line 165 at Ninject.Activation.Providers.StandardProvider.GetValue(IContext context, ITarget target) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:line 114 at Ninject.Activation.Providers.StandardProvider.<>c__DisplayClass4.<Create>b__2(ITarget target) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:line 96 at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext() at System.Linq.Buffer`1..ctor(IEnumerable`1 source) at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source) at Ninject.Activation.Providers.StandardProvider.Create(IContext context) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:line 96 at Ninject.Activation.Context.Resolve() in c:\Projects\Ninject\ninject\src\Ninject\Activation\Context.cs:line 157 at Ninject.KernelBase.<>c__DisplayClass10.<Resolve>b__c(IBinding binding) in c:\Projects\Ninject\ninject\src\Ninject\KernelBase.cs:line 386 at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext() at System.Linq.Enumerable.SingleOrDefault[TSource](IEnumerable`1 source) at Ninject.Planning.Targets.Target`1.GetValue(Type service, IContext parent) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Targets\Target.cs:line 197 at Ninject.Planning.Targets.Target`1.ResolveWithin(IContext parent) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Targets\Target.cs:line 165 at Ninject.Activation.Providers.StandardProvider.GetValue(IContext context, ITarget target) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:line 114 at Ninject.Activation.Providers.StandardProvider.<>c__DisplayClass4.<Create>b__2(ITarget target) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:line 96 at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext() at System.Linq.Buffer`1..ctor(IEnumerable`1 source) at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source) at Ninject.Activation.Providers.StandardProvider.Create(IContext context) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:line 96 at Ninject.Activation.Context.Resolve() in c:\Projects\Ninject\ninject\src\Ninject\Activation\Context.cs:line 157 at Ninject.KernelBase.<>c__DisplayClass10.<Resolve>b__c(IBinding binding) in c:\Projects\Ninject\ninject\src\Ninject\KernelBase.cs:line 386 at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext() at System.Linq.Enumerable.SingleOrDefault[TSource](IEnumerable`1 source) at Ninject.Planning.Targets.Target`1.GetValue(Type service, IContext parent) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Targets\Target.cs:line 197 at Ninject.Planning.Targets.Target`1.ResolveWithin(IContext parent) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Targets\Target.cs:line 165 at Ninject.Activation.Providers.StandardProvider.GetValue(IContext context, ITarget target) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:line 114 at Ninject.Activation.Providers.StandardProvider.<>c__DisplayClass4.<Create>b__2(ITarget target) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:line 96 at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext() at System.Linq.Buffer`1..ctor(IEnumerable`1 source) at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source) at Ninject.Activation.Providers.StandardProvider.Create(IContext context) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:line 96 at Ninject.Activation.Context.Resolve() in c:\Projects\Ninject\ninject\src\Ninject\Activation\Context.cs:line 157 at Ninject.KernelBase.<>c__DisplayClass10.<Resolve>b__c(IBinding binding) in c:\Projects\Ninject\ninject\src\Ninject\KernelBase.cs:line 386 at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext() at System.Linq.Enumerable.SingleOrDefault[TSource](IEnumerable`1 source) at Ninject.Web.Mvc.NinjectDependencyResolver.GetService(Type serviceType) in c:\Projects\Ninject\ninject.web.mvc\mvc3\src\Ninject.Web.Mvc\NinjectDependencyResolver.cs:line 56 at System.Web.Mvc.DefaultControllerFactory.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) --- End of inner exception stack trace --- at System.Web.Mvc.DefaultControllerFactory.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) at System.Web.Mvc.DefaultControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType) at System.Web.Mvc.DefaultControllerFactory.CreateController(RequestContext requestContext, String controllerName) at System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase httpContext, IController& controller, IControllerFactory& factory) at System.Web.Mvc.MvcHandler.<>c__DisplayClass6.<BeginProcessRequest>b__2() at System.Web.Mvc.SecurityUtil.<>c__DisplayClassb`1.<ProcessInApplicationTrust>b__a() at System.Web.Mvc.SecurityUtil.<GetCallInAppTrustThunk>b__0(Action f) at System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust(Action action) at System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust[TResult](Func`1 func) at System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state) at System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state) at System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData) at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) 

UPDATE:

Below is the code from HomeController:

 public class HomeController : Controller { #region Declaration public ICommonService _commonService { get; set; } #endregion #region Constructor public HomeController() { } public HomeController(ICommonService commonService) { this._commonService = commonService; } #endregion public ActionResult Index() { return View(); } 

Constructor of CommonService and CommonRepository:

 public class CommonService : ICommonService { #region Declaration private readonly ICommonRepository _repository; #endregion #region Constructor public CommonService(ICommonRepository repository) { this._repository = repository; } #endregion public class CommonRepository : ICommonRepository { #region Declaration private DBContainer _context = new DBContainer(); #endregion #region Constructor public CommonRepository() { } #endregion 

Am I missing any other links here?

Answer 1

Here's how constructor selection in Ninject works:

• If the constructor has the [Inject] attribute, it is used. If multiple constructors have an [Inject] attribute, Ninject will throw a NotSupportedException.
• If none of the constructors has the [Inject] attribute, Ninject will select the one that has more parameters that Ninject understands how to allow.
• If no constructors are defined, Ninject will select the default dimensionless constructor.

In your case, Ninject will most likely not choose a constructor without parameters, because it thinks it knows how to enable ICommonService. Try decorating your constructor without parameters with the [Inject] attribute if you want Ninject to use it or continue investigating why ICommonService is not allowed.

Answer 2

If you recently redirected an MVC application from .NET 4.0 to 4.5, or vice versa, then you will get the same symptom. It is fixed by referencing the correct .NET DLLs for the target.

If you use Ninject, Ninject.MVC3 and Ninject.Web.Common nugets, you will find all .NET objects there.

Answer 3

Quote from https://github.com/ninject/ninject/wiki/Injection-Patterns :

The basic DI pattern is constructor injection. When you activate an instance of the Ninject type, select one of the types of constructors to use, applying the following rules in the following order: -

If the constructor has the [Inject] attribute, it is used (but if you apply the attribute to several, Ninject will throw a NotSupportedException at runtime upon detection).

If none of the constructors has an [Inject] attribute, Ninject will select the one that has more parameters that Ninject understands how to allow.

If no constructors are defined, Ninject will select a constructor with no default parameters (if any).