Ninject Dependency Injection for SignalR

问题:

In my NinjectWebCommon.cs file, under CreateKernel method I am applying the injection like this

private static IKernel CreateKernel()
    {
        var kernel = new StandardKernel();
        kernel.Bind<Func<IKernel>>().ToMethod(ctx => () => new Bootstrapper().Kernel);
        kernel.Bind<IHttpModule>().To<HttpApplicationInitializationHttpModule>();

        RegisterServices(kernel);

        // Web API Injection
        GlobalConfiguration.Configuration.DependencyResolver = new NinjectDependencyResolver(kernel);                     

        // SignalR Injection
        GlobalHost.DependencyResolver = new SignalR.Ninject.NinjectDependencyResolver(kernel);

        return kernel;
    }

I was thinking that should do it for me but i keep getting an error at the SignalR injection that

"Cannot implicitly convert type 'SignalR.Ninject.NinjectDependencyResolver' to 'Microsoft.AspNet.SignalR.IDependencyResolver'"

Any idea what the problem is?

回答1:

I am not sure if you have found the answer or not. They have changed the way DI works in SignalR as of version 1.0.0 and the SignalR.Ninject packages doesn't work - I have written a small blog post on this: http://myrandomcodesnippets.wordpress.com/2013/03/29/ninject-dependency-injection-with-signalr-1-0-1/

Basically you need to create your own implementation of this which is the same as the SignalR.Ninject implementation:

GlobalHost.DependencyResolver = new SignalRNinjectDependencyResolver(kernel);

When you create the new class it will want to inherit from IDependancyResolver don't bother with this and use:

public class SignalRNinjectDependencyResolver : DefaultDependencyResolver
{
    private readonly IKernel _kernel;

    public SignalRNinjectDependencyResolver(IKernel kernel)
    {
        _kernel = kernel;
    }

    public override object GetService(Type serviceType)
    {
        return _kernel.TryGet(serviceType) ?? base.GetService(serviceType);
    }

    public override IEnumerable<object> GetServices(Type serviceType)
    {
        return _kernel.GetAll(serviceType).Concat(base.GetServices(serviceType));
    }
}

Hope this helps.