Ninject Web API Setup

NinjectDependencyResolver.cs

using System;
using System.Diagnostics.Contracts;
using System.Web.Http.Dependencies;
using Ninject;
using Ninject.Activation.Blocks;

namespace MyProject
{
    public class NinjectDependencyResolver : NinjectDependencyScope, IDependencyResolver
    {
        private readonly IKernel kernel;

        public NinjectDependencyResolver(IKernel kernel) 
            : base(kernel.BeginBlock())
        {
            Contract.Requires<ArgumentNullException>(kernel != null);
            this.kernel = kernel;
        }

        public bool CanDisposeOfKernel
        {
            get { return kernel != null && !kernel.IsDisposed; }
        }

        public IDependencyScope BeginScope()
        {
            IActivationBlock activationBlock = kernel.BeginBlock();
            return new NinjectDependencyScope(activationBlock);
        }

        protected override void Dispose(bool isDisposing)
        {
            base.Dispose(true);
            if (CanDisposeOfKernel)
                kernel.Dispose();
        }
    }
}

NinjectDependencyScope.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web.Http.Dependencies;
using Ninject.Activation;
using Ninject.Activation.Blocks;
using Ninject.Parameters;

namespace MyProject
{
    public class NinjectDependencyScope : IDependencyScope
    {
        private readonly IActivationBlock activationBlock;

        public NinjectDependencyScope(IActivationBlock activationBlock)
        {
            this.activationBlock = activationBlock;
        }

        public bool CanDisposeOfActivationBlock
        {
            get { return activationBlock != null && !activationBlock.IsDisposed; }
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        public object GetService(Type serviceType)
        {
            return GetServices(serviceType).FirstOrDefault();
        }

        public IEnumerable<object> GetServices(Type serviceType)
        {
            IRequest request = activationBlock.CreateRequest(serviceType, null, new IParameter[] { }, true, false);
            IEnumerable<object> services = activationBlock.Resolve(request);
            return services;
        }

        protected virtual void Dispose(bool isDisposing)
        {
            if (CanDisposeOfActivationBlock)
                activationBlock.Dispose();
        }
    }
}

I have usually been throwing these two files in my ~/App_Start folder of my application. If I were smarter, I would probably just go ahead and add them to a teeny tiny library so I didn't have to constantly retype them all the damn time.

I have read that I shouldn't be disposing of my IKernel instance in my NinjectDependencyResolver class, because this can really mess up anything being declared with .ToSingleton(). I haven't tested this, so I can't back that claim up.