c# – 在使用MVC 6的Web API中找不到IServiceCollection

在ConfigureServices方法中,将添加突出显示的代码：

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<ITodoRepository,TodoRepository>();
        }
    }
}

它显示错误……

The type or namespace name ‘IServiceCollection’ could not be found (are you missing a using directive or an assembly reference?)