HttpClient.GetStringAsync 正在返回一个"Result"对象？

Question

我正在尝试使用GetStringAsync方法从我自己的API中检索JSON列表。 当我得到它时，它返回为"结果"对象而不仅仅是一个字符串？

然后我尝试将 JSON 数组反序列化为列表，但收到错误.

这是调试器中返回的字符串从 HttpCLient.GetStringAsync 中的样子：

"{"Result":[{"id":92,"name":"Chris Hemsworth","birthDate":"1983-8-11","role":"Producer","originalList":null},{"id":90,"name":"Jennifer Aniston","birthDate":"1969-2-11","role":"Producer","originalList":null},{"id":40,"name":"Edward Norton","birthDate":"1969-8-18","role":"Writer","originalList":null}],"Id":71,"Exception":null,"Status":5,"IsCanceled":false,"IsCompleted":true,"CreationOptions":0,"AsyncState":null,"IsFaulted":false}"

尝试将 JSON 对象转换为字符串时出现的异常：

Newtonsoft.Json.JsonSerializationException: 'Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[BuisnessLogic.Actor]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List<T>) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object.Path 'Result', line 1, position 10.'

更新：

这是代码：

var celebrities = JsonConvert.DeserializeObject<List<Actor>>(await client.GetStringAsync($"{serverAddress}/values/{GET_CELEBS_COMMAND}"));

演员类：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace BuisnessLogic
{
public class Actor
{
public int id { get; set; }
public string name { get; set; }
public string birthDate { get; set; }
public string role { get; set; }
public List<Actor> originalList { get; set; }
public Actor(string name, string birthDate, string role)
{
this.name = name;
this.birthDate = birthDate;
this.role = role;
}
public Actor()
{
}
public override string ToString()
{
return "Person: " + id + "" + name + " " + birthDate + " " + role;
}
}
}

编辑 2 ：

控制器：

using BuisnessLogic;
using System.Web.Mvc;
namespace WebApplication12.Controllers
{
public class ValuesController : Controller
{
public ILogic _Ilogic;
public ValuesController(ILogic logic)
{
_Ilogic = logic;
}
// GET api/values
public ActionResult GetActors()
{
return Json(_Ilogic.GetAllActorsAsync(), JsonRequestBehavior.AllowGet);
}
}
}

数据管理类：

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.IO;
using System.Configuration;
using System.Collections.Concurrent;
using System.Threading.Tasks;
using System.Linq;

namespace BuisnessLogic
{
public class Logic : ILogic
{
static string filePath;
private static ConcurrentDictionary<string, Actor> originalList;
const string BACKUP = @"D:backup.txt";
static Logic()
{
originalList = new ConcurrentDictionary<string, Actor>();
filePath = ConfigurationManager.AppSettings["tempList"];
File.Copy(filePath, BACKUP, true);
SaveOriginal();
}

public async static Task<List<Actor>> GetCelebritiesInner()
{
return originalList.Values.ToList();
}
public async Task<List<Actor>> GetAllActorsAsync()
{
return await GetCelebritiesInner();
}


// Try to read the data from the Json and initialize it. if failed , initialize with whatever it got. return 
private static List<Actor> ReadActorsFromJson(string json)
{
List<Actor> celebListReadFromFile;
try
{
var celebJson = File.ReadAllText(json);
celebListReadFromFile = JsonConvert.DeserializeObject<List<Actor>>(celebJson);
}
catch (Exception ex)
{
celebListReadFromFile = new List<Actor>();
// Empty list/whatever it got in it
}
return celebListReadFromFile;
}
public async Task RemoveActorAsync(string name)
{
if (originalList.TryRemove(name, out Actor removedActor))
{
var jsonToWrite = JsonConvert.SerializeObject(await GetCelebritiesInner());
try
{
File.WriteAllText(filePath, jsonToWrite);
}
catch (Exception ex)
{
//Unable to remove due to an error.
}
}
}
public async Task ResetAsync()
{
UpdateFile();
}
//Saving the actor, adding the name as key & object as value.
public static void SaveOriginal()
{
foreach (var currCeleb in ReadActorsFromJson(filePath))
{
originalList.TryAdd(currCeleb.name, currCeleb);
}
}
public static void UpdateFile()
{
File.WriteAllText(filePath, string.Empty);
var text = File.ReadAllText(BACKUP);
File.WriteAllText(filePath, text);
}
}
}

转到 uri 并获取字符串的更新方法：

public async void update()
{
var b = await client.GetStringAsync($"{serverAddress}/values/{GET_CELEBS_COMMAND}");
var celebrities = JsonConvert.DeserializeObject<List<Actor>>(b);
foreach (Actor actor in celebrities)
{
actorBindingSource.Add(actor);
}
}

Answer 1

问题中显示的JSON是Task<T>的序列化实例，其中包括Result、AsyncState和IsFaulted等属性。很明显，这应该是T的序列化实例(在您的情况下List<Actor>(，这通常意味着某处缺少await。

这个"缺失的await"在你的ValuesController.GetActors中，它把ILogic.GetAllActorsAsync的结果传递到Json。这最终会导致传入Task<List<Actor>>的实例，而不仅仅是List<Actor>。为了解决这个问题，请使用await，如下所示：

public async Task<ActionResult> GetActors()
{
return Json(await _Ilogic.GetAllActorsAsync(), JsonRequestBehavior.AllowGet);
}

这也需要制作GetActorsasync，如我上面所示。

Answer 2

首先将**Result**替换为Result。

var stringResult = await HttpCLient.GetStringAsync().Replace("**Result**", "Result");

其次创建与 json 结果具有相同属性的类。

public class JsonResult
{
public List<ResultObject> Result { get; set; }
public int Id { get; set; }
public string Exception { get; set; }
public int Status { get; set; }
public bool IsCanceled { get; set; }
public bool IsComplete { get; set; }
public int CreationOptions { get; set; }
public string AsyncState { get; set; }
public bool IsFaulted { get; set; }
}
public class ResultObject
{
public int id { get; set; }
public string name { get; set; }
public string birthDate { get; set; }
public string role { get; set; }
public string originalList { get; set; }
}

然后使用以下命令反序列化字符串：

var resultObject = JsonConvert.DeserializeObject<JsonResult>(result);

resultObject将包含整个结果。