WebApi, Ninject and MediatR binding issues

[jbogard]

WebApi, Ninject and MediatR binding issues

[anghiulian]

Thank you! The solution you provided works!

[kiwipiet]

It looks like your bindings is not setup correctly.
Could you post your code where you setup your Ninject kernel?

[anghiulian]

Hi @kiwipiet,

The code inside NinjectWebCommon is as follows:

 private static IKernel CreateKernel()
        {
            var kernel = new StandardKernel();
            try
            {
                kernel.Bind<Func<IKernel>>().ToMethod(ctx => () => new Bootstrapper().Kernel);
                kernel.Bind<IHttpModule>().To<HttpApplicationInitializationHttpModule>();
                RegisterServices(kernel);
                return kernel;
            }
            catch
            {
                kernel.Dispose();
                throw;
            }
        } 
private static void RegisterServices(IKernel kernel)
        {
            kernel.Components.Add<IBindingResolver, ContravariantBindingResolver>();
            kernel.Bind(scan => scan.FromAssemblyContaining<IMediator>).SelectAllClasses().BindDefaultInterface());           
            kernel.Bind(scan => scan.FromAssemblyContaining(typeof(IAsyncRequestHandler<,>)).SelectAllClasses().BindAllInterfaces());
            kernel.Bind(scan => scan.FromAssemblyContaining(typeof(IAsyncRequest<>)).SelectAllClasses().BindAllInterfaces());
            kernel.Bind<SingleInstanceFactory>().ToMethod(ctx => t => ctx.Kernel.Get(t));
            kernel.Bind<MultiInstanceFactory>().ToMethod(ctx => t => ctx.Kernel.GetAll(t));
}

And I try to inject it in a ApiController like so:

        private readonly IMediator mediator;

        public PeopleController(IMediator mediator)
        {
            this.mediator = mediator;
        }

[kiwipiet]

kernel.Bind(scan => scan.FromAssemblyContaining(typeof(IAsyncRequestHandler<,>)).SelectAllClasses().BindAllInterfaces()); kernel.Bind(scan => scan.FromAssemblyContaining(typeof(IAsyncRequest<>)).SelectAllClasses().BindAllInterfaces());

These are your problem lines. The assembly it is going to find in both cases is 'MediatR.dll'. And this assembly has already been bound in:
kernel.Bind(scan => scan.FromAssemblyContaining<IMediator>).SelectAllClasses().BindDefaultInterface());

If you have one assembly that contains your handlers and requests then only register that assembly once and don't re-register MediatR.dll

This is clearly a web app, and if you have all your requests and handlers in the web app assembly you could do the following:

kernel.Bind(scan => scan.From(Assembly.GetExecutingAssembly()).SelectAllClasses().InNamespaceOf(type).BindAllInterfaces());

or

kernel.Bind(scan => scan.FromAssemblyContaining<MyAsyncRequestHandler>).SelectAllClasses().BindDefaultInterface());
where MyAsyncRequestHandler is one of your handlers.