使用 Json.Net 反序列化时出现错误“无法反序列化当前 JSON 数组”答案

【问题标题】：Getting an error "Cannot deserialize the current JSON array" when deserializing using Json.Net使用 Json.Net 反序列化时出现错误“无法反序列化当前 JSON 数组”
【发布时间】：2015-05-06 08:02:27
【问题描述】：

我有一个字符串：

[
  {
    "key": "key1",
    "value": "{'Time':'15:18:42','Data':'15:18:42'}",
    "duration": 5
  },
  {
    "key": "key1",
    "value": "{'Time':'15:18:42','Data':'15:18:42'}",
    "duration": 5
  }
]

我的模型课：

public class CPacket
{
    public string key { get; set; }
    public string value { get; set; }
    public int duration { get; set; }
}

我使用 Json.Net，我想将下面的字符串转换为 Json Oject。

CPacket c = JsonConvert.DeserializeObject<CPacket>(strPostData);

但它错误：

Newtonsoft.Json.dll 中出现“Newtonsoft.Json.JsonSerializationException”类型的异常，但未在用户代码中处理
附加信息：无法将当前 JSON 数组（例如 [1,2,3]）反序列化为类型 'QuoteAPI.Models.CPacket'，因为该类型需要 JSON 对象（例如 {"name":"value"}）才能正确反序列化.

【问题讨论】：

标签： c# json json.net

【解决方案1】：

您的 JSON 表示 CPacket 对象的数组，而不仅仅是单个对象。你需要反序列化成一个列表。

List<CPacket> list = JsonConvert.DeserializeObject<List<CPacket>>(strPostData);

【讨论】：

【解决方案2】：

    {
        var url = "http://jsonplaceholder.typicode.com/posts";

        var webClient = new WebClient();
        var responseStr = webClient.DownloadString(url);

        //JObject jResponse = JObject.Parse(responseStr);
        JArray jArray = JArray.Parse(responseStr);


        List<User> userList = new List<User>();

        foreach (var item in jArray)
        {
            User user = new User();

            user.UserID = Convert.ToInt32(item["userId"]);
            user.ID = Convert.ToInt32(item["id"]);
            user.Title = Convert.ToString(item["title"]);
            user.Body = Convert.ToString(item["body"]);

            userList.Add(user);
        }







public partial class Search : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string url = "http://jsonplaceholder.typicode.com/posts";
        var webClient = new WebClient();
        var responseStr = webClient.DownloadString(url);
        JArray jArray = JArray.Parse(responseStr);



        List<Class1> userList = new List<Class1>();

        foreach (var item in jArray)
        {
            Class1 user = new Class1();


            user.userId = Convert.ToInt32(item["userId"]);
            user.id = Convert.ToInt32(item["id"]);
            user.title = Convert.ToString(item["title"]);
            user.body = Convert.ToString(item["body"]);

            userList.Add(user);
        }
        Repeater1.DataSource = userList;
        Repeater1.DataBind();
        var myClass = _download_serialized_json_data<List<Class1>>(url);
        WebRequest request = WebRequest.Create(url);
        WebResponse ws = request.GetResponse();
        //Stream stream1 = response.GetResponseStream();
        //StreamReader sr = new StreamReader(stream1);
        //string strsb = sr.ReadToEnd();
        //object objResponse = JsonConvert.DeserializeObject(strsb, JSONResponseType);
        DataContractJsonSerializer jsonSerializer =
                new DataContractJsonSerializer(typeof(List<Class1>));
        object objResponse = jsonSerializer.ReadObject(ws.GetResponseStream());
        List<Class1> jsonResponse
        = objResponse as List<Class1>;
        List<Class1> photos = (List<Class1>)jsonSerializer.ReadObject(ws.GetResponseStream());
    }

    private static T _download_serialized_json_data<T>(string url) where T : new()
    {
        using (var w = new WebClient())
        {
            var json_data = string.Empty;
            // attempt to download JSON data as a string
            try
            {
                json_data = w.DownloadString(url);
            }
            catch (Exception) { }
            // if string with JSON data is not empty, deserialize it to class and return its instance
            return !string.IsNullOrEmpty(json_data) ? JsonConvert.DeserializeObject<T>(json_data) : new T();
        }
    }
}



}

【讨论】：

请详细说明你的答案，而不是张贴代码墙。