How can you inject an asp.net (mvc2) custom membership provider using Ninject?

Question

OK, so I've been working on this for hours. I've found a couple of posts here, but nothing that actually resolves the problem. So, let me try it again...

I have an MVC2 app using Ninject and a custom membership provider.

If I try and inject the provider using the ctor, I get an error: 'No parameterless constructor defined for this object.'

public class MyMembershipProvider : MembershipProvider
{
    IMyRepository _repository;

    public MyMembershipProvider(IMyRepository repository)
    {
        _repository = repository;
    }

I've also been playing around with factories and Initialize(), but everything is coming up blanks.

Any thoughts/examples?

Sagunto

Answer 1

This is how I was able to do this:

1) I created a static helper class for Ninject

public static class NinjectHelper
{
    public static readonly IKernel Kernel = new StandardKernel(new FooServices());

    private class FooServices : NinjectModule
    {
        public override void Load()
        {
            Bind<IFooRepository>()
                .To<EntityFooRepository>()
                .WithConstructorArgument("connectionString",
                    ConfigurationManager.ConnectionStrings["FooDb"].ConnectionString);
        }
    }
}

2) Here is my Membership override:

    public class FooMembershipProvider : MembershipProvider
    {
        private IFooRepository _FooRepository;

        public FooMembershipProvider()
        {
            NinjectHelper.Kernel.Inject(this);
        }

        [Inject]
        public IFooRepository Repository 
        { 
            set
            {
                _FooRepository = value;
            }
        }
        ...

With this approach it doesn't really matter when the Membership provider is instantiated.

Susette

You tied the IoC with the application here :( – Melissamelisse

Answer 2

The Membership provider model can only instantiate a configured provider when it has a default constructor. You might try this using the Service Locator pattern, instead of using Dependency Injection. Example:

public class MyMembershipProvider : MembershipProvider
{
    IMyRepository _repository;

    public MyMembershipProvider()
    {
        // This example uses the Common Service Locator as IoC facade, but
        // you can change this to call NInject directly if you wish.
        _repository = ServiceLocator.Current.GetInstance<IMyRepository>;
    }

Loritalorn

Adding to this, you can also use property injection - mark some properties [Inject] and then do a Kernel.Inject(this) (Not sure if the SL pattern / CSL thing you're using exposes such a facility though) – Twinkling

I've having the same problem, and have tried Ruben's suggestion to no avail. I think it's happening because the Membership provider is being created before Ninject is configured. – Thyself

I don't think property injection can work in this scenario, because it is not NInject that will create an instance of the MyMembershipProvider, but it is the System.Web.Security.Membership sub system that will instantiate a new instance. – Loritalorn

@Reuben - do you put the Kernel.Inject(this) inside the membership provider constructor? – Monk

Answer 3

I had the same problem at the exact same spot in the book. It wasn't until later on in the book that I noticed there were two separate web.config files. I initially placed my connectionString key in the wrong web.config file. It wasn't until I placed the connectionString in the correct web.config file that the 'no parameterless constructor' error went away.

Elanaeland