Web API 返回嵌套的 JSON 值

Question

我正在处理由 web api 返回的 JSON 结构，但是有一个问题。

比如说，我有两张桌子，Teams 和 Players。他们由TeamID 加入（团队为PK，玩家为FK）。

我希望我的 API 调用返回一些类似于以下的 JSON 格式：

[
    {
        TeamId: 1,
        TeamName: 'Chicago Bulls',
        TeamPlayers: [
            {PlayerId: 1, PlayerName: 'Pau Gasol'},
            {PlayerId: 2, PlayerName: 'Derrick Rose'},
            {PlayerId: 3, PlayerName: 'Joakim Noah'},
            {PlayerId: 4, PlayerName: 'Jimmy Butler'},
            {PlayerId: 5, PlayerName: 'Taj Gibson'}]
    },
    {
        TeamId: 2,
        TeamName: 'Cleveland Cavaliers',
        TeamPlayers: [
            {PlayerId: 1, PlayerName: 'Lebron James'},
            {PlayerId: 2, PlayerName: 'Kyrie Irving'},
            {PlayerId: 3, PlayerName: 'Anderson Varejao'},
            {PlayerId: 4, PlayerName: 'Dion Waiters'},
            {PlayerId: 5, PlayerName: 'Shawn Marion'}]
    },
    {
        TeamId: 3,
        TeamName: 'Los Angeles Clippers',
        TeamPlayers: [
            {PlayerId: 1, PlayerName: 'Chris Paul'},
            {PlayerId: 2, PlayerName: 'Blake Griffin'},
            {PlayerId: 3, PlayerName: 'DeAndre Jordan'},
            {PlayerId: 4, PlayerName: 'Jamal Crawford'},
            {PlayerId: 5, PlayerName: 'Matt Barnes'}]
    }
]

控制器：

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using System.Web.Http;
using System.Web.Http.Description;
using MyApp.Models;

namespace MyApp.Controllers
{
    public class TeamsController : ApiController
    {
        private DataModel db = new DataModel();

        // GET: api/teams
        public IQueryable<TeamsWithPlayers> GetTeamsAndPlayers()
        {
            var query = from x in db.Teams
                        join y in db.Players on x.TeamId equals y.TeamId
                        select
                        {
                            // This is where I need some help...
                        }
        }
    }
}

TeamAndPlayer 类：

namespace MyApp.Models
{
    public class TeamAndPlayers
    {
        public int TeamId { get; set; }
        public string TeamName { get; set; }
        public Players players { get; set; }
    }
}

玩家类：

namespace MyApp.Models
{
    public class Players 
    {
        public int TeamId { get; set; }
        public int PlayerId { get; set; }
        public string PlayerName { get; set; }
    }
}

有人可以提供一些见解吗？

Answer 1

   var query = from x in db.Teams
    join y in db.Players on x.TeamId equals y.TeamId
    select new TeamsWithPlayers
    {
      TeamId = x.Id,
      TeamName= x.TeamName,
      Players = y
    }.ToList();

Answer 2

• 我将假设 JSON 结构是此处的真实来源，而不是模型 (TeamWithPlayers/Players) - 请参阅我的 cmets。

• 我的解决方案假定您正在使用实体框架从数据库中检索数据，因为我使用的是“包含”方法，但可以将其替换为使用“加入”。

1- 将 TeamDto 和 PlayerDto 类定义为：

public class TeamDto
{
    public int TeamId { get; set; }
    public string TeamName { get; set; }
    public IEnumerable<PlayerDto> TeamPlayers { get; set; }
}

public class PlayerDto
{
    public int PlayerId { get; set; }
    public string PlayerName { get; set; }
}

2- 您的 TeamsController 将如下所示：

public class TeamsController : ApiController
{
    private readonly TeamDbContext _dbContext = new TeamDbContext();

    // GET api/teams
    public IEnumerable<TeamDto> GetTeamsAndPlayers()
    {
        var teams = _dbContext
            .Teams
            .Include("Players") // Load the players associated with each Team, (this depends on your declaration, but you mentioned that there is a FK from Player => TeamId)
            // you can use the join if you like or if you don't use entity framework where you cannot call Include, but the following code will stay the same 
            .Select(t => new TeamDto
            {
                TeamId = t.TeamId,
                TeamName = t.TeamName,
                TeamPlayers = t.Players.Select(p => new PlayerDto
                    {
                        PlayerId = p.PlayerId, 
                        PlayerName = p.PlayerName
                    })
            }).ToList();

        return teams;
    }
}

希望对您有所帮助。

Answer 3

喜欢建议的答案，非常有帮助！

我使用建议的答案为 msyelf 制定了类似的学习解决方案，然后尝试将上述解决方案代码适合 getbyid 方法。

我遇到了一些困难，但想出了以下可行的解决方案，以防有人像我一样偶然发现这篇文章并想知道如何通过 getbyid 方法使用上述解决方案。

这是VS创建的默认WebAPI getbyid方法：

    // GET: api/teams/5
    [ResponseType(typeof(teams))]
    public IHttpActionResult Getteams(long id)
    {
        teams teams = db.teams.Find(id);
        if (teams == null)
        {
            return NotFound();
        }

       return Ok(teams);
    }

这里是更新后的 Getbyid 方法，使用了本文中答案所用的结构：

    // GET: api/teams/5
    [ResponseType(typeof(teams))]
    public IHttpActionResult Getteams(long id)
    {
            var teams = _dbContext
            .Teams
            .Where(t => t.TeamId == id)
            .Include("Players")
            .Select(t => new TeamDto
            {
                TeamId = t.TeamId,
                TeamName = t.TeamName,
                TeamPlayers = t.Players.Select(p => new PlayerDto
                    {
                        PlayerId = p.PlayerId, 
                        PlayerName = p.PlayerName
                    })
            })
        });

        if (request == null)
        {
            return NotFound();
        }

        return Ok(requests);
    }