c# - 无法将 Json 字符串反序列化为列表对象

Question

我有一个像这样的 json 字符串:

{"bwEventList": {

    "events": [

      {
        "summary" : "Leisure Classes Beginning Today",
        "subscriptionId" : "",
        "calPath" : "%2Fpublic%2Fcals%2FMainCal",
        "guid" : "CAL-02a786e6-45f207c3-0147-11c6cf10-000074e3bedework%40lsu.edu",
        "recurrenceId" : "",
        "link" : "",
        "eventlink" : "http://calendar.apps.lsu.edu/feeder/feeder/event/eventView.do?b=de&calPath=%2Fpublic%2Fcals%2FMainCal&guid=CAL-02a786e6-45f207c3-0147-11c6cf10-000074e3bedework%40lsu.edu&recurrenceId=",
        "status" : "CONFIRMED",
        "start" : {
          "allday" : "true",
          "shortdate" : "11/22/14",
          "longdate" : "November 22, 2014",
          "dayname" : "Saturday",
          "time" : "12:00 AM",
          "utcdate" : "20141122T060000Z",
          "datetime" : "20141122",
          "timezone" : ""
        },
        "end" : {
          "allday" : "true",
          "shortdate" : "11/22/14",
          "longdate" : "November 22, 2014",
          "dayname" : "Saturday",
          "time" : "12:00 AM",
          "utcdate" : "20141122T060000Z",
          "datetime" : "20141122",
          "timezone" : ""
        }

我这样写我的模型:

    public class Event
{
    [JsonProperty(PropertyName ="summary")]
    public string summary { get; set; }
    [JsonProperty(PropertyName ="subscriptionId")]
    public string subscriptionId { get; set; }
    [JsonProperty(PropertyName ="calPath")]
    public string calPath { get; set; }
    [JsonProperty(PropertyName ="guid")]
    public string guid { get; set; }
    [JsonProperty(PropertyName ="reccurenceId")]
    public string recurrenceId { get; set; }
    [JsonProperty(PropertyName ="link")]
    public string link { get; set; }
    [JsonProperty(PropertyName ="eventlink")]
    public string eventlink { get; set; }
    [JsonProperty(PropertyName ="status")]
    public string status { get; set; }
    [JsonProperty(PropertyName ="start")]
    public Start start { get; set; }
    [JsonProperty(PropertyName ="end")]
    public End end { get; set; }
    [JsonProperty(PropertyName ="location")]
    public Location location { get; set; }
    [JsonProperty(PropertyName ="contact")]
    public Contact contact { get; set; }
    [JsonProperty(PropertyName ="calendar")]
    public Calendar calendar { get; set; }
    [JsonProperty(PropertyName ="categories")]
    public List<string> categories { get; set; }
    [JsonProperty(PropertyName ="description")]
    public string description { get; set; }
    [JsonProperty(PropertyName ="cost")]
    public string cost { get; set; }

}

public class BwEventList
{
    public List<Event> events { get; set; }
}

    public class Start
    {
        [JsonProperty(PropertyName ="allday")]
        public string allday { get; set; }
        [JsonProperty(PropertyName ="shortdate")]
        public string shortdate { get; set; }
        [JsonProperty(PropertyName ="longdate")]
        public string longdate { get; set; }
        [JsonProperty(PropertyName ="dayname")]
        public string dayname { get; set; }
        [JsonProperty(PropertyName ="time")]
        public string time { get; set; }
        [JsonProperty(PropertyName ="utcdate")]
        public string utcdate { get; set; }
        [JsonProperty(PropertyName ="datetime")]
        public string datetime { get; set; }
        [JsonProperty(PropertyName ="timezone")]
        public string timezone { get; set; }
    }

    public class End
    {
        public string allday { get; set; }
        public string shortdate { get; set; }
        public string longdate { get; set; }
        public string dayname { get; set; }
        public string time { get; set; }
        public string utcdate { get; set; }
        public string datetime { get; set; }
        public string timezone { get; set; }
    }

我正在尝试反序列化字符串，然后将列表中的每个事件显示到 XML(android) 上。下面是我如何获取字符串并将其反序列化

public async Task<List<ReveilleApp.Core.Models.Event>> GetItems(string feedUrl)
    {
        try{
        using (WebClient webclient = new WebClient ()) {
            WebClient n = new WebClient ();

            var json =  await n.DownloadStringTaskAsync (feedUrl);

            var model = JsonConvert.DeserializeObject<List<ReveilleApp.Core.Models.Event>>(json);

            return model;
            }
        }
            catch(Exception ex)
            {
                Console.WriteLine(ex.Message);
                return null;

            }


        }

返回项目以填充 ListView 。在异常(exception)情况下我得到这个错误

    Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[ReveilleApp.Core.Models.Event]' 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.

我尝试了很多解决方案，但都没有用

Answer 1

您的模型与 Json 列不匹配。

莱昂内尔修正了模型:

但我也想对您的方法提出一些更正建议:

public async Task<RootObject> GetItems(string feedUrl)
{
        try
        {
            using (WebClient webclient = new WebClient()) 
            {
                 var json =  await webclient.DownloadStringTaskAsync(feedUrl);
                 var model = JsonConvert.DeserializeObject<RootObject>(json);
                 return model;
            }
        }
        catch(Exception ex)
        {
                Console.WriteLine(ex.Message);
                return null;
        }
}

您也可以将其作为列表获取。

当你调用这个方法时

var root = GetItems(string feedUrl) as RootObject; // Ex call for method
if(root != null && root.bwEventList != null && root.bwEventList.Count > 0) // Just checking the conditions to make sure everthing is OK.
{
     List<Event> eventsList = root.bwEventList.events; // Here you will get it as a list.
}