我试图将一个json数据反序列化为一个模型类,但是我失败了.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<CountryModel>>(result);
return output.First();
}
}
这是我的模型如何：
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<Country> 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Json我到了这里：http://api.worldbank.org/incomeLevels/LIC/countries?format=json
这是我得到的错误：
Cannot deserialize JSON array into type ‘Mvc4AsyncSample.Models.CountryModel’. Line 1,position 1.
解决方法
你必须编写一个自定义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<List<Country>>(reader);
reader.Read(); //end array
return model;
}
public override void WriteJson(JsonWriter writer,object value,JsonSerializer serializer)
{
throw new NotImplementedException();
}
}
并用该转换器标记CountryModel(我也必须将一些int转换为字符串)：
[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<Country> 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; }
}
那么你应该能够像这样反序列化：
var output = JsonConvert.DeserializeObject<CountryModel>(result);
