无法反序列化JSON数组类型 - Json.NET [英] Cannot deserialize JSON array into type - Json.NET
问题描述
我想反序列化JSON数据转换成一个模型类,但我失败了。这是我做的:
公共CountryModel GetCountries(){
使用(Web客户端的客户端=新的Web客户端()){
VAR的结果= client.DownloadString(http://api.worldbank.org/incomeLevels/LIC/countries?format=json);
无功输出= JsonConvert.DeserializeObject<列表< CountryModel>>(结果);
返回output.First();
}
}
这是我的模式是这样的:
公共类CountryModel
{
公众诠释页{获得;组; }
公众诠释页{获得;组; }
公众诠释Per_Page {获得;组; }
公众诠释共{获得;组; }
公开名单<国家>国家{获得;组; }
}
公共类国家
{
公众诠释编号{获得;组; }
公共字符串ISO2 code {获得;组; }
公共字符串名称{;组; }
公共区域地区{获得;组; }
}
公共类地区
{
公众诠释编号{获得;组; }
公共字符串值{获得;组; }
}
您可以看到的Json我得到这里:的http:// API。 worldbank.org/incomeLevels/LIC/countries?format=json
这是我的错误:
无法反序列化JSON数组类型Mvc4AsyncSample.Models.CountryModel。行1,位置1。
您必须编写自定义的 JsonConverter
:
公共类CountryModelConverter:JsonConverter
{
公众覆盖布尔CanConvert(类型的objectType)
{
如果(的objectType == typeof运算(CountryModel))
{
返回true;
}
返回false;
}
公众覆盖对象ReadJson(JsonReader读者,类型的objectType
,反对existingValue,JsonSerializer串行)
{
reader.Read(); //启动阵列
//reader.Read(); //启动对象
JObject OBJ =(JObject)serializer.Deserialize(读卡器);
// {页面:1,页:1,per_page:50,共:35}
VAR模型=新CountryModel();
model.Page = Convert.ToInt32(((JValue)OBJ [页])值。);
model.Pages = Convert.ToInt32(((JValue)OBJ [页])值);
model.Per_Page = Int32.Parse((字符串)((JValue)OBJ [per_page])值。);
model.Total = Convert.ToInt32(((JValue)OBJ [总])值。);
reader.Read(); //结束对象
model.Countries = serializer.Deserialize<列表<国家>>(读卡器);
reader.Read(); //端阵列
回归模型;
}
公众覆盖无效WriteJson(JsonWriter作家,对象值
,JsonSerializer串行)
{
抛出新的NotImplementedException();
}
}
和标签 CountryModel
与转换器(我也不得不改用一些 INT
到字符串
):
[JsonConverter(typeof运算(CountryModelConverter))]
公共类CountryModel
{
公众诠释页{获得;组; }
公众诠释页{获得;组; }
公众诠释Per_Page {获得;组; }
公众诠释共{获得;组; }
公开名单<国家>国家{获得;组; }
}
公共类国家
{
公共字符串ID {获得;组; }
公共字符串ISO2 code {获得;组; }
公共字符串名称{;组; }
公共区域地区{获得;组; }
}
公共类地区
{
公共字符串ID {获得;组; }
公共字符串值{获得;组; }
}
然后,你应该能够反序列化是这样的:
无功输出= JsonConvert.DeserializeObject< CountryModel>(结果);
I am trying to deserialize a json data into a model class but I am failing. Here is what I do:
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();
}
}
This is how my model looks like:
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; }
}
You can see the Json I am getting here: http://api.worldbank.org/incomeLevels/LIC/countries?format=json
This is the error I get:
Cannot deserialize JSON array into type 'Mvc4AsyncSample.Models.CountryModel'. Line 1, position 1.
You have to write a custom 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();
}
}
And tag the CountryModel
with that converter (I also had to switch some int
to 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<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; }
}
Then you should be able to deserialize like this:
var output = JsonConvert.DeserializeObject<CountryModel>(result);
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