c# - Ninject and MVC3: Dependency injection to action filters

Question

I've found loads of inconclusive articles and questions on how to do property injection on an ActionFilter in ASP.NET MVC3 using Ninject.

Could someone give me a clear example please?

Here's my custom auth attribute.

public class CustomAuthorizeAttribute : AuthorizeAttribute
{
    [Inject]
    public IService Service { get; set; }

    [Inject]
    public IAuthenticationHelper AuthenticationHelper { get; set; }

    public override void OnAuthorization(AuthorizationContext filterContext)
    {
         //My custom code
    }
 }

I am using the WebActivator to set up Ninject

[assembly: WebActivator.PreApplicationStartMethod(typeof(MyProject.Web.AppStart_NinjectMvc3), "Start")]

 namespace MyProject.Web {

   public static class AppStart_NinjectMvc3 {
        public static void RegisterServices(IKernel kernel) {

           //Binding things
    }

    public static void Start() {
        // Create Ninject DI Kernel 
        IKernel kernel = new StandardKernel();

        // Register services with our Ninject DI Container
        RegisterServices(kernel);

        // Tell ASP.NET MVC 3 to use our Ninject DI Container 
        DependencyResolver.SetResolver(new NinjectServiceLocator(kernel));
    }

  }
}

My service and helper are never injected. What do I need to change?

Answer 1

In my opinion there is a better solution than using filter attributes. See my blogposts about an alternative way of declaring filters using Ninject. It does not require property injection and uses constructor injection instead:

http://www.planetgeek.ch/2010/11/13/official-ninject-mvc-extension-gets-support-for-mvc3/ http://www.planetgeek.ch/2011/02/22/ninject-mvc3-and-ninject-web-mvc3-merged-to-one-package/