如何通过JToken.ToObject<>()方法使用JsonConverter? [英] How to use a JsonConverter with JToken.ToObject<>() method?
问题描述
我正在将大型JSON文件成功读取到JObjects中.我反序列化的一种类型具有System.Drawing.Color类型的属性.此属性的JSON具有一个表示颜色的整数值.当我尝试执行ToObject()时,我会得到
I'm reading a large JSON file successfully into JObjects. One of the types I'm deserializing into has a property of type System.Drawing.Color. The JSON for this property has an integer value representing the color. When I try to do a ToObject() I get
将值16711680转换为"System.Drawing.Color"时出错.
Error converting value 16711680 to type 'System.Drawing.Color'.
解决方案似乎是一个简单的JsonConverter,它可以从整数转换为Color,但是我不知道如何将转换器与现有的JObject一起使用.我缺少明显的东西吗?
The solution seems to be a simple JsonConverter that can convert from an integer to a Color but I can't find out how to use the converter with an existing JObject. Am I missing something obvious?
推荐答案
ToObject<T>
的重载可以接受JsonSerializer
.序列化器有一个Converters
集合,您可以在其中添加转换器.
There is an overload of ToObject<T>
that accepts a JsonSerializer
. The serializer has a Converters
collection into which you can add your converter.
这是一个简短的演示:
using System;
using System.Drawing;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
public class Program
{
public static void Main()
{
JObject obj = JObject.Parse(@"{ ""Color"" : 16711680 }");
JsonSerializer serializer = new JsonSerializer();
serializer.Converters.Add(new ColorConverter());
Color c = obj["Color"].ToObject<Color>(serializer);
Console.WriteLine(c.ToString());
}
}
class ColorConverter : JsonConverter
{
public override bool CanConvert(Type objectType)
{
return (objectType == typeof(Color));
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
writer.WriteValue(((Color)value).ToArgb());
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
return Color.FromArgb(Convert.ToInt32(reader.Value));
}
}
输出:
Color [A=0, R=255, G=0, B=0]
提琴: https://dotnetfiddle.net/ZA22mD
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