Accessing ninject kernel in Application_Start

Question

I am using Ninject and the MVC3 extension installed with nuget. My kernel setup code is in the App_Start/NinjectMVC3.cs file. Everything works great in controllers, but I can't figure out how to (properly) bind interfaces in the Global.asax.cs MvcApplication code.

I ended up using a hack (creating a public NinjectMVC3.GetKernel() method that returns bootstrap.kernel). However, that will be deprecated, and there must be a proper way to do this that I am not seeing.

Here is my code:

public class LogFilterAttribute : ActionFilterAttribute
{
    private IReportingService ReportingService { get; set; }
    public LogFilterAttribute( IReportingService reportingService )
    {
        this.ReportingService  = reportingService;
    }
    ...
}

public class MvcApplication : System.Web.HttpApplication
{
    public static void RegisterGlobalFilters( GlobalFilterCollection filters )
    {
        filters.Add( new HandleErrorAttribute() );
        filters.Add( new LogFilterAttribute()  );
    }
    ...
    protected void Application_Start()
    {
        ...
        RegisterGlobalFilters( GlobalFilters.Filters );
        // NOTE hack:
        var kernel = NinjectMVC3.GetKernel();
        var logger = kernel.Get<ILogger>();
        var bw = new BackgroundWork(logger);
        Application["BackgroundWork"] = bw;
        bw.Start();
    }
}

There are two interfaces I am interested in. The first is just binding an object to a Global variable (the ILogger for the BackgroundWork).

And the second is for an ActionFilter. I read http://www.planetgeek.ch/2010/11/13/official-ninject-mvc-extension-gets-support-for-mvc3/, but I don't see how it plugs into the actual registration (filter.Add).

I don't want to use the Property Inject if I can avoid it.

Any thoughts on the proper way to do this? Thanks

Answer 1

MVC 3 introduces the DependencyResolver which is populated into a singleton, and the Ninject extension supports it. You could use that in your MvcApplication class if you need it:

protected void Application_Start()
{
    // ...
    var logger = DependencyResolver.Current.GetService<ILogger>();
}

Now I should point out that it is unnecessary to do this with action filters. In Ninject.MVC3 you are supposed to use the BindFilter syntax, like so:

// Declare empty attribute
public class MyFilterAttribute : FilterAttribute { }

// Dependency module
public class MyModule : NinjectModule
{
    public override void Load()
    {
        // Other bindings
        // ...
        this.BindFilter<MyActionFilter>(FilterScope.Action, 1)
            .WhenControllerHas<MyFilterAttribute>();
    }
}

Note that you have to use this because BindFilter is an extension method, and you also have to reference the Ninject.Web.Mvc.FilterBindingSyntax namespace.