c# Json.NET ToJson() FromJson()

问题

I understand the value of creating an external JsonConverter classes however in many cases I find it unnecessarily cumbersome.

Is there a general way to tell JSon.NET that if a class has a string ToJson() method use that for serialization and if the class has a void FromJson(string json) method use that for deserialization ?

Or/And also for immutable types if a class has a static T FromJson(string json) use that ?

回答1:

We need a special conveter:

namespace Newtonsoft.Json {
  class JsonManualConverter : JsonConverter {
    public override bool CanConvert(Type t) => t.GetMethod("ToJson") != null && t.GetMethod("FromJson") != null;

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) =>
      objectType.GetMethod("FromJson").Invoke(new object(), new object[] { JRaw.Create(reader).ToString() });

    public override void WriteJson(JsonWriter writer, object o, JsonSerializer serializer) =>
      writer.WriteRaw(o.GetType().GetMethod("ToJson").Invoke(o, new object[] { }) as string);
  }
}

Then we can simply do:

  [JsonConverter(typeof(JsonManualConverter))]
  class MyClass {
    public string ToJson() => // serialize and return json string
    static public MyClass FromJson(string json) => // deserialize and return a MyClass instance
    ...
  }

and Json.Net will use these methods

I also found it useful to create:

namespace Newtonsoft.Json {
    public static string ToJson(object value) => JsonConvert.SerializeObject(value);
    public static string ToJson(object value, Formatting formatting) => JsonConvert.SerializeObject(value, formatting);
    public static string ToJson(object value, params JsonConverter[] converters) => JsonConvert.SerializeObject(value, converters);
    public static string ToJson(object value, Formatting formatting, params JsonConverter[] converters) => JsonConvert.SerializeObject(value, formatting, converters);
    public static string ToJson(object value, JsonSerializerSettings settings) => JsonConvert.SerializeObject(value, settings);
    public static string ToJson(object value, Type type, JsonSerializerSettings settings) => JsonConvert.SerializeObject(value, type, settings);
    public static string ToJson(object value, Formatting formatting, JsonSerializerSettings settings) => JsonConvert.SerializeObject(value, formatting, settings);
    public static string ToJson(object value, Type type, Formatting formatting, JsonSerializerSettings settings) => JsonConvert.SerializeObject(value, type, formatting, settings);

    public static T FromJson<T>(string value) => JsonConvert.DeserializeObject<T>(value);
    public static T FromJson<T>(string value, params JsonConverter[] converters) => JsonConvert.DeserializeObject<T>(value, converters);
    public static T FromJson<T>(string value, JsonSerializerSettings settings) => JsonConvert.DeserializeObject<T>(value, settings);
}

and use JConvert.ToJson(obj) and JConvert<T>.FromJson(json) as shortcuts

来源：https://stackoverflow.com/questions/51256196/c-sharp-json-net-tojson-fromjson

标签

json.net