如何将 JSON 表示为对象类型？ （Unity3D 使用 RESTful Web 服务）

Question

https://i.imgur.com/2t2gO0g.png

错误：“JSON 必须表示对象类型”。但只有当我添加 "{\"meshDatas\":" + jsonResult + "}";行得通吗（抱歉解释得不好）

遇到问题 (https://i.imgur.com/XDzokfj.png)，“JSON 必须表示对象类型”。

如何让我的 Rest Api 将 List 作为 JSON 对象返回？

实际 Json 响应：https://i.imgur.com/GUzHKG8.png

关注了这些视频：https://www.youtube.com/watch?v=TrOLTrIX9Yk && https://www.youtube.com/watch?v=00gSBOTI4tg 然后修改了从数据库中获取 MeshData 的代码

试过了： string jsonResult = System.Text.Encoding.UTF8.GetString(www.downloadHandler.data);

var newJson = "{\"meshDatas\":" + jsonResult + "}";
MeshDataList meshDataList = JsonUtility.FromJson(newJson);

这有效并将问题缩小到 Rest Api 的格式，但现在我不知道如何让 Api 发送正确的格式...

Image_For.Context https://i.imgur.com/tWj8Ohf.png

//RestClient.cs (Unity)
using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Networking;

public class RestClient : MonoBehaviour
{
    private static RestClient _instance;

    public static RestClient Instance 
    {
        get
        {
            if (_instance == null)
            {
                _instance = FindObjectOfType<RestClient>();
                if (_instance == null)
                {
                    GameObject go = new GameObject();
                    go.name = typeof(RestClient).Name;
                    _instance = go.AddComponent<RestClient>();
                    DontDestroyOnLoad(go);
                }
            }
            return _instance;
        }
    }

    public IEnumerator Get(string url, System.Action<MeshDataList> callBack)
    {
        using (UnityWebRequest www = UnityWebRequest.Get(url))
        {
            yield return www.SendWebRequest();
            if (www.isNetworkError)
            {
                Debug.Log(www.error);
            }
            else
            {
                if (www.isDone)
                {
                    try
                    {
                        string jsonResult = System.Text.Encoding.UTF8.GetString(www.downloadHandler.data);

                        var newJson = "{\"meshDatas\":" + jsonResult + "}";                        
                        MeshDataList meshDataList = JsonUtility.FromJson<MeshDataList>(newJson);

                        callBack(meshDataList);
                    }
                    catch(Exception e)
                    {
                        Debug.Log(e.Message);
                    }


                }
            }

        }
    }

//Game.cs (Unity)
public class Game : MonoBehaviour
{
    public string WEB_URL = "";

    // Start is called before the first frame update
    void Start()
    {
        StartCoroutine(RestClient.Instance.Get(WEB_URL, GetMeshDatas));        
    }

    void GetMeshDatas(MeshDataList meshDataList)
    {
        foreach (MeshData meshData in meshDataList.meshDatas)
        {

            Debug.Log("MeshData Xsize :" + meshData.xsize);
            Debug.Log("MeshData Zsize :" + meshData.zsize);
            Debug.Log("MeshData Width :" + meshData.width);
            Debug.Log("MeshData Height :" + meshData.height);
            Debug.Log("MeshData Scale :" + meshData.scale);
            Debug.Log("MeshData OffsetX :" + meshData.offsetX);
            Debug.Log("MeshData OffsetY :" + meshData.offsetY);
            Debug.Log("MeshData Id :" + meshData.id);

        }
    }

}

//UMM.API.Dummy.Controllers
[Route("api/[controller]")]
    [ApiController]
    public class MeshDatasController : Controller
    {
        private readonly UMMClientDEMContext _context;

        public MeshDatasController(UMMClientDEMContext context)
        {
            _context = context;
        }

        // GET: api/MeshDatas
        [HttpGet]
        public async Task<ActionResult<IEnumerable<MeshData>>> GetMeshData()
        {
            return await _context.MeshData.ToListAsync();
        }

        // GET: api/MeshDatas/{n}
        [HttpGet("{id}")]
        public async Task<ActionResult<MeshData>> GetMeshData(int id)
        {
            var meshData = await _context.MeshData.FindAsync(id);
            //MeshData meshData = MeshData.Single(mbox => mbox.Id == Id);

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

            return meshData;
        }

//UMM.API.Dummy.Models
namespace UMM.API.Dummy.Models
{
    [JsonObject, Serializable]
    public class MeshData
    {
        public int? Xsize { get; set; }
        public int? Zsize { get; set; }
        public int? Width { get; set; }
        public int? Height { get; set; }
        public int? Scale { get; set; }
        public int? OffsetX { get; set; }
        public int? OffsetY { get; set; }
        public int Id { get; set; }
    }

预期结果 https://i.imgur.com/E3lmFKW.png 从 Rest Api 后面获取正确格式化的 Json 数据，例如

{"meshDatas":[{"xsize":20,"zsize":20,"width":256,"height":256,"scale":20,"offsetX":100,"offsetY": 100,"id":1}]}

Answer 1

我想你想要这样的东西

// GET: api/MeshDatas
        [HttpGet]
        public async Task<ActionResult<MeshDataListObject>> GetMeshData() //Returnable type changed here
        {
            MeshDataListObject returnable = new MeshDataListObject();
            returnable.meshDatas = await _context.MeshData.ToListAsync();
            return returnable;
        }

public class MeshDataListObject {
    public IEnumerable<MeshData> meshDatas; //Something to hold the result you want to return. 
//This will be serialized to something like {"meshDatas":[]}
}