Question

I’m using SignalR 0.5.2 and I’m trying to get a DependencyResolver set up using Unity. I’ve written the simplest code I can. I have a hub that I’m trying to inject into which looks like this:

public class SimpleHub : Hub
{
    private readonly ITestService _service;

    public SimpleHub(ITestService service)
    {
        _service = service;
    }

    public void Update()
    {
        Clients.callback("Kevin");
    }
}

and a DependencyResolver that looks like this:

public class UnityDependencyResolver : DefaultDependencyResolver
{
    private readonly IUnityContainer _container;

    public UnityDependencyResolver(IUnityContainer container)
    {
        _container = container;
    }

    public override object GetService(Type serviceType)
    {
        if (_container.IsRegistered(serviceType))
        {
            return _container.Resolve(serviceType);
        }
        return base.GetService(serviceType);
    }

    public override IEnumerable<object> GetServices(Type serviceType)
    {
        if (_container.IsRegistered(serviceType))
        {
            return _container.ResolveAll(serviceType);
        }
        return base.GetServices(serviceType);
    }
}

I register the dependency resolver in Global.asax

protected void Application_Start()
{
    IUnityContainer container = new UnityContainer();
    InitializeContainer(container);
    SignalR.IDependencyResolver resolver = new UnityDependencyResolver(container);
    GlobalHost.DependencyResolver = resolver;
    RouteTable.Routes.MapHubs();
    // more MVC stuff here
}

where InitializeContainer register the ITestService in Unity

The resolver “works” in that it’s getting called for all the SignalR types, and if I leave my hub with a default constructor it all gets loaded. However the resolver never gets asked to resolve the ITestService interface.

I’ve also tried passing the resolver to MapHubs, still no luck. I’ve also tried property injection using the [Dependency] attribute and that didn’t work either.

Do I need to register the resolver with MVC as well? (I have tried that by implementing both IDependecyResolver interfaces but get an exception telling me the resolver doesn’t implement IServiceLocator)

Answer 1

So I’ve sort of fixed this. I wondered if the fact that the Hub was registered with the signalr container and the interface was registered with the Unity container was causing the issue. So I registered the Hub with Unity and then everything works.

This sort of makes sense as there are two containers.

Is this the standard behaviour?