无法将JSON数组反序列化为类型–Json.NET

我试图将json数据反序列化为模型类,但我失败了。 这是我做的:

public CountryModel GetCountries() { using (WebClient client = new WebClient()) { var result = client.DownloadString("http://api.worldbank.org/incomeLevels/LIC/countries?format=json"); var output = JsonConvert.DeserializeObject<List>(result); return output.First(); } } 

这就是我的模型的样子:

 public class CountryModel { public int Page { get; set; } public int Pages { get; set; } public int Per_Page { get; set; } public int Total { get; set; } public List Countries { get; set; } } public class Country { public int Id { get; set; } public string Iso2Code { get; set; } public string Name { get; set; } public Region Region { get; set; } } public class Region { public int Id { get; set; } public string Value { get; set; } } 

你可以看到我来到这里的Json: http : //api.worldbank.org/incomeLevels/LIC/countries? format = json

这是我得到的错误:

无法将JSON数组反序列化为“Mvc4AsyncSample.Models.CountryModel”类型。 第1行,第1位。

你必须编写一个自定义的JsonConverter

  public class CountryModelConverter : JsonConverter { public override bool CanConvert(Type objectType) { if (objectType == typeof(CountryModel)) { return true; } return false; } public override object ReadJson(JsonReader reader, Type objectType , object existingValue, JsonSerializer serializer) { reader.Read(); //start array //reader.Read(); //start object JObject obj = (JObject)serializer.Deserialize(reader); //{"page":1,"pages":1,"per_page":"50","total":35} var model = new CountryModel(); model.Page = Convert.ToInt32(((JValue)obj["page"]).Value); model.Pages = Convert.ToInt32(((JValue)obj["pages"]).Value); model.Per_Page = Int32.Parse((string) ((JValue)obj["per_page"]).Value); model.Total = Convert.ToInt32(((JValue)obj["total"]).Value); reader.Read(); //end object model.Countries = serializer.Deserialize>(reader); reader.Read(); //end array return model; } public override void WriteJson(JsonWriter writer, object value , JsonSerializer serializer) { throw new NotImplementedException(); } } 

并使用该转换器标记CountryModel (我还必须将一些int切换为string ):

  [JsonConverter(typeof(CountryModelConverter))] public class CountryModel { public int Page { get; set; } public int Pages { get; set; } public int Per_Page { get; set; } public int Total { get; set; } public List Countries { get; set; } } public class Country { public string Id { get; set; } public string Iso2Code { get; set; } public string Name { get; set; } public Region Region { get; set; } } public class Region { public string Id { get; set; } public string Value { get; set; } } 

然后你应该能够像这样反序列化:

 var output = JsonConvert.DeserializeObject(result); 

这看起来像是一种(不太好)尝试用JSON表示XML。 JSON看起来像这样:

 [ { "page": 1, … }, [ { "id": "AFG", "name": "Afghanistan", … }, { "id": "BDI", "name": "Burundi", … }, … ] ] 

虽然合理的JSON(偶然会很好地映射到您的模型)看起来像这样:

 { "page": 1, …, "countries": [ { "id": "AFG", "name": "Afghanistan", … }, { "id": "BDI", "name": "Burundi", … }, … ] } 

如果您确定要使用JSON(而不是XML),可以先将JSON反序列化为JSON.NET的对象模型,然后将其反序列化到模型中:

 var json = client.DownloadString("http://api.worldbank.org/incomeLevels/LIC/countries?format=json"); var array = (JArray)JsonConvert.DeserializeObject(json); var serializer = new JsonSerializer(); var countryModel = serializer.Deserialize(array[0].CreateReader()); countryModel.Countries = serializer.Deserialize>(array[1].CreateReader()); return countryModel; 

不要忘记将您的Id属性更改为string ,因为它们就是这样。

您的模型与JSON结构不匹配。 看起来你错过了最后6个属性。

 { "id": "AFG", "iso2Code": "AF", "name": "Afghanistan", "region": { "id": "SAS", "value": "South Asia" }, "adminregion": { "id": "SAS", "value": "South Asia" }, "incomeLevel": { "id": "LIC", "value": "Low income" }, "lendingType": { "id": "IDX", "value": "IDA" }, "capitalCity": "Kabul", "longitude": "69.1761", "latitude": "34.5228" 

}