在Web API上的多对多关系

我正在努力学习Entity Framework Core。不幸的是，当你创建一个多对多的关系时，它似乎要求一个连接类。请参见下面的类结构：

Person（人）

Sport（运动）

PersonSport（人-运动）

一个人有很多种运动，而一种运动也有很多人参与。在使用Entity Framework时，我会在Person类中放置一个Sport集合，在Sport类中放置一个Person集合。然而，现在我必须创建PersonSport类。请参见下面的API控制器（这是复制问题所需的唯一代码）：

namespace WebApplication1.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class PersonController : Controller
    {
        [Route("")]
        [ProducesResponseType(typeof(Person), (int)HttpStatusCode.OK)]
        //[ProducesResponseType(typeof(IEnumerable), (int)HttpStatusCode.OK)]
        [HttpGet]
        public async Task GetPerson()
        {
            Person p1 = new Person { Id = Guid.NewGuid() };
            Sport s1 = new Sport { Id = Guid.NewGuid(), Description = "Football" };
            Sport s2 = new Sport { Id = Guid.NewGuid(), Description = "Running" };
            PersonSport ps1 = new PersonSport { Person = p1, PersonId = p1.Id, Sport = s1, SportId = s1.Id };
            PersonSport ps2 = new PersonSport { Person = p1, PersonId = p1.Id, Sport = s2, SportId = s2.Id };
            List personSports = new List();
            personSports.Add(ps1);
            personSports.Add(ps2);
            p1.AssignSports(personSports);
            return Ok(p1);
        }
    }
    public class Entity
    {
        public Guid Id { get; set; }
    }
    public class Person : Entity
    {
        private readonly List _personSports;
        public IReadOnlyCollection PersonSports => _personSports.AsReadOnly();
        //public Guid Id { get; set; }
        public Person()
        {
            _personSports = new List();
        }
        public void AssignSports(IEnumerable personSports)
        {
            this._personSports.AddRange(personSports);
        }
    }
    public class Sport : Entity
    {
        //public Guid Id { get; set; }
        public string Description { get; set; }
    }
    public class PersonSport
    {
        public Person Person { get; set; }
        public Sport Sport { get; set; }
        public Guid PersonId { get; set; }
        public Guid SportId { get; set; }
    }
}

我调试Web API项目并导航到：http://localhost:57320/api/Person，看到如下结果：

注意到JSON格式不正确。如果我尝试从控制台应用程序/单元测试应用程序中使用Web API，我会看到以下错误：

System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
   --- End of inner exception stack trace ---
   at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.ThrowException(SocketError error)
   at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.GetResult(Int16 token)
   at System.Net.Http.HttpConnection.FillAsync()
   at System.Net.Http.HttpConnection.ChunkedEncodingReadStream.CopyToAsyncCore(Stream destination, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.GetStringAsyncCore(Task`1 getTask)
   at ConsoleApp1.Program.CallWebAPI() 

我该如何解决这个问题？我用于消费Web API的代码如下：

HttpClient enquiryClient = new HttpClient();
var responseString = await enquiryClient.GetStringAsync("http://localhost:57320/api/Person");
var response = JsonConvert.DeserializeObject(responseString);