Question

In my MVC 2 project, I originally used Ninject 2 and wrote this version of the NinjectControllerFactory:

public class NinjectControllerFactory : DefaultControllerFactory
{
    private IKernel kernel = new StandardKernel(new HandiGamerServices());

    protected override IController GetControllerInstance(System.Web.Routing.RequestContext requestContext, Type controllerType)
    {
        try
        {
            if (controllerType == null)
            {
                return base.GetControllerInstance(requestContext, controllerType);
                // return null;
            }
        }
        catch (HttpException ex)
        {
            if (ex.GetHttpCode() == 404)
            {
                IController errorController = kernel.Get<ErrorController>();
                ((ErrorController)errorController).InvokeHttp404(requestContext.HttpContext);

                return errorController;
            }
            else
            {
                throw ex;
            }
        }

        return (IController)kernel.Get(controllerType);
    }

Of most importance is the retrieval of my ErrorController, which allows me to gracefully handle a multitude of HTTP errors.

The problem is that I upgraded to the MVC 2 extension via Nuget, so a NinjectControllerFactory is already provided. Would it be possible to use my own override of GetControllerInstance? If so, how?

Answer 1

I do exactly this, and for precisely the same reason. In Global.asax.cs, I add this to my OnApplicationStarted override (declared virtual in NinjectHttpApplication):

ControllerBuilder.Current.SetControllerFactory(
    new MyControllerFactory(ControllerBuilder.Current.GetControllerFactory()));

This means you’re creating your own controller factory, but providing it with the default implementation to do the heavy lifting.

Then define your controller factory like so:

public class MyControllerFactory : IControllerFactory
{
    private IControllerFactory defaultFactory;

    public MyControllerFactory(IControllerFactory defaultFactory)
    {
        this.defaultFactory = defaultFactory;
    }

    public IController CreateController(RequestContext requestContext, string controllerName)
    {
        try
        {
            var controller = defaultFactory.CreateController(requestContext, controllerName);
            return controller;
        }
        catch (HttpException e)
        {
            // Pasted in your exception handling code here:
            if (ex.GetHttpCode() == 404)
            {
                IController errorController = kernel.Get<ErrorController>();
                ((ErrorController)errorController).InvokeHttp404(requestContext.HttpContext);

                return errorController;
            }
            else
            {
                throw ex;
            }
        }
    }

    public SessionStateBehavior GetControllerSessionBehavior(RequestContext requestContext, string controllerName)
    {
        return defaultFactory.GetControllerSessionBehavior(requestContext, controllerName);
    }

    public void ReleaseController(IController controller)
    {
        defaultFactory.ReleaseController(controller);
    }
}

As you can see, we’re just using the default (Ninject) controller factory for most purposes unless it can’t find the page. For obtaining the error controller, you can either pass in the kernel as you were already doing, or just call defaultFactory.CreateController using the error controller name.