Simple Injector registration problem in SignalR

问题

I set DI in my Controller as shown below and tied to register IHubContext as it seen on

Controller:

public class DemoController : Controller
{
    private IHubContext<DemoHub> context;

    public DemoController(IHubContext<DemoHub> context)
    {
        this.context = context;
    }
}

Global.asax:

protected void Application_Start()
{
    AreaRegistration.RegisterAllAreas();
    RouteConfig.RegisterRoutes(RouteTable.Routes);
    FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
    BundleConfig.RegisterBundles(BundleTable.Bundles);
    var container = new Container();
    container.Options.DefaultScopedLifestyle = new WebRequestLifestyle();



    container.Register<IHubContext, IHubContext>(Lifestyle.Scoped);

    // or 

    container.Register<IHubContext>(Lifestyle.Scoped);

    // code omitted
}

But when I debug my app, encounter "System.ArgumentException: 'The given type IHubContext is not a concrete type. Please use one of the other overloads to register this type. Parameter name: TImplementation'" error. So, how can I register IHubContext properly?

回答1:

Since ASP.NET MVC doesn't have built in dependency injection for SignalR hub context you have to obtain a context instance using GlobalHost.ConnectionManager. With this you can register a dependency with your container that creates IHubContext instance. Considering you have typed hub

public class DemoHub : Hub<ITypedClient>
{
}

and interface

public interface ITypedClient
{
    void Test();
}

register dependency as the following

container.Register<IHubContext<ITypedClient>>(() =>
{
    return GlobalHost.ConnectionManager.GetHubContext<DemoHub, ITypedClient>();
}, Lifestyle.Scoped);

And the controller should look like

public class DemoController : Controller
{
    private IHubContext<ITypedClient> context;

    public DemoController(IHubContext<ITypedClient> context)
    {
        this.context = context;
    }
}

来源：https://stackoverflow.com/questions/57256906/simple-injector-registration-problem-in-signalr