c#将json反序列化为List

Question

我有这段代码可以从 API link 中检索 Json 字符串。 Json 被反序列化并 returned 到文本框。只要只有 1 个 Json 值，它就可以完美运行，returned 超过 1 个值时它会崩溃并出现此错误：

Additional information: Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'GW2_tradingPost.RootObject' because the type requires a JSON object (e.g. {"name":"value"}) to deserialize correctly.

To fix this error either change the JSON to a JSON object (e.g. {"name":"value"}) or change the deserialized type to an array or a type that implements a collection interface (e.g. ICollection, IList) like List that can be deserialized from a JSON array. JsonArrayAttribute can also be added to the type to force it to deserialize from a JSON array.

我的研究之所以会发生这种情况，是因为 Json 不是列表，因此无处存放。

我试过这段代码和各种类似的代码。

List<RootObject> list = JsonConvert.DeserializeObject<List<RootObject>>(jsonReader.ToString());
return list;

这将 return 错误：

Error 1 Cannot implicitly convert type 'System.Collections.Generic.List' to 'GW2_tradingPost.RootObject' e:\mega\gw2_tradingpost\gw2_tradingpost\api_request.cs 34

我不完全理解它的意思。

这是我的完整代码。

api_Request.cs

public class api_Request
    {
        public RootObject GetApi(string url)
        {

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);

            try
            {
                WebResponse response = request.GetResponse();
                using (Stream responseStream = response.GetResponseStream())
                {
                 StreamReader reader = new StreamReader(responseStream, Encoding.UTF8);
                var jsonReader = new JsonTextReader(reader);
                var serializer = new JsonSerializer();
                return serializer.Deserialize<RootObject>(jsonReader);
            }
            }
            catch (WebException ex)
            {
                WebResponse errorResponse = ex.Response;
                using (Stream responseStream = errorResponse.GetResponseStream())
                {
                    StreamReader reader = new StreamReader(responseStream, Encoding.GetEncoding("utf-8"));
                    String errorText = reader.ReadToEnd();
                    // log errorText
                }
                throw;
            }
        }

    }


    public class Buy
    {
        public int listings { get; set; }
        public int unit_price { get; set; }
        public int quantity { get; set; }
    }

    public class Sell
    {
        public int listings { get; set; }
        public int unit_price { get; set; }
        public int quantity { get; set; }
    }

    public class RootObject
    {
        public int id { get; set; }
        public List<Buy> buys { get; set; }
        public List<Sell> sells { get; set; }
    }

Form1.cs

 private void button1_Click(object sender, EventArgs e)
        {
            RootObject RootObject = new RootObject();
            api_Request api_Request = new api_Request();
            richTextBox1.Text = api_Request.GetApi("https://api.guildwars2.com/v2/commerce/listings").id.ToString();
        }

在这个 json 中是一个单一的 ID，所以这个工作正常。 https://api.guildwars2.com/v2/commerce/listings/19684

但是像这里一样检索多个 ID 时，它会中断。 https://api.guildwars2.com/v2/commerce/listings

Answer 1

您为多个 ID return 提供的 link 整数数组。我建议这样解析：

var ids = JsonConvert.DeserializeObject<int[]>(jsonReader.ToString())

正如您所说，您的代码适用于单个项目，因此您可以将现有代码用于每个单独的请求，而不是点击 https://api.guildwars2.com/v2/commerce/listings，而是点击 https://api.guildwars2.com/v2/commerce/listings/{id}，您可以使用 string.Format() 在需要的地方添加。

认真考虑 int[] 中有多少个 id return 是你真正想要获取根对象的，据我所知，它是 returns ，你会提出很多请求。

Answer 2

这是一个简单的解决方案，可以获取所有 ID 的列表，但需要花费大量时间才能完成所有这些

  List<RootObject> rootobject = new List<RootObject>();
    using (var webclient = new WebClient())
    {
        var Ids = webclient.DownloadString(" https://api.guildwars2.com/v2/commerce/listings");
        foreach (var id in Ids.Substring(1, s.Length-2).Split(','))
        {
            string url = string.Format("{0}/{1}","https://api.guildwars2.com/v2/commerce/listings",id);
            var res = webclient.DownloadString(url);
            var jsonObject = JsonConvert.DeserializeObject<RootObject>(res);
            rootobject.Add(jsonObject);
        }


    }

c#将json反序列化为List

c# Deserialize json into List

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