Ninject Dependency Injection on Action Method Parameters in MVC3

Question

I would like to use NInject.MVC3 to resolve which concrete class to instantiate when calling an Action method on a controller. So for example:

    [HttpPost]
    public ActionResult Index(IMyModelInterface model)
    {
        // do something

        return View();
    }

Obviously without dependency injection, MVC3 could not instantiate the IMyModelInterface, but I could bind that interface to a concrete class that implements this interface.

I have tried this and just get the error from the MVC framework trying to instantiate the interface.

So, first of all, is this a bad thing to attempt to do?

If it is not a stupid thing to do, how do I do it?

If it is a bad thing to do, how else should I do this. I have considered using a ViewModel then copying the parameters across? I am slightly reluctant to do this, as my model contains all the nice validation attributes for the view to use - and would have to duplicate this in the ViewModel, which seems to add maintenance overhead.

I have seen the SO question with doing this using Autofac.

I am using the most recent versions of NInject and NInject.MVC3 from the Nuget package.

Answer 1

Ninject does not allow you to inject dependencies in methods like that, as you can read here.
You should inject your dependencies through controller's constructor, properties or setter methods.

Answer 2

You could probably implement your own model binder to do this.

Subclass DefaultModelBinder, override CreateModel and use Ninject in this method return the appropriate type.