IServiceCollection not found in web API with MVC 6
<p>I am working with web API with MVC 6, here I am going in order to inject the repository into the controller, we need to register it with the DI container. Open the Startup.cs file.</p>

<p>In the <code>ConfigureServices</code> method, going to add the highlighted code:</p>

<pre><code>using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Owin;
using Owin;
using TodoApi.Models;

[assembly: OwinStartup(typeof(TodoApi.Startup))]

namespace TodoApi
{
    public partial class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            ConfigureAuth(app);
        }

        public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc();
            // Add our repository type
            services.AddSingleton&lt;ITodoRepository, TodoRepository&gt;();
        }
    }
}
</code></pre>

<p>Its showing the error...</p>

<blockquote>
  <p>The type or namespace name 'IServiceCollection' could not be found (are you missing a using directive or an assembly reference?)</p>
</blockquote>