Can I serialize nested properties to my class in one operation with Json.net?

Question

Lets say I have a model like:

public class MyModel
{
    public string Name { get; set; }
    public string[] Size { get; set; }
    public string Weight { g         


        

Answer 1

This should work:

public class MyModelJsonConverter : JsonConverter
{
    public override bool CanRead
    {
        get { return true; }
    }

    public override bool CanConvert(Type objectType)
    {
        return objectType == typeof(MyModel);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        if (objectType != typeof(MyModel))
        {
            throw new ArgumentException("objectType");
        }

        switch (reader.TokenType)
        {
            case JsonToken.Null:
            {
                return null;
            }
            case JsonToken.StartObject:
            {
                reader.Read();
                break;
            }
            default:
            {
                throw new JsonSerializationException();
            }
        }

        var result = new MyModel();
        bool inDetails = false;

        while (reader.TokenType == JsonToken.PropertyName)
        {
            string propertyName = reader.Value.ToString();
            if (string.Equals("name", propertyName, StringComparison.OrdinalIgnoreCase))
            {
                reader.Read();
                result.Name = serializer.Deserialize(reader);
            }
            else if (string.Equals("size", propertyName, StringComparison.OrdinalIgnoreCase))
            {
                if (!inDetails)
                {
                    throw new JsonSerializationException();
                }

                reader.Read();
                result.Size = serializer.Deserialize(reader);
            }
            else if (string.Equals("weight", propertyName, StringComparison.OrdinalIgnoreCase))
            {
                if (!inDetails)
                {
                    throw new JsonSerializationException();
                }

                reader.Read();
                result.Weight = serializer.Deserialize(reader);
            }
            else if (string.Equals("details", propertyName, StringComparison.OrdinalIgnoreCase))
            {
                reader.Read();

                if (reader.TokenType != JsonToken.StartObject)
                {
                    throw new JsonSerializationException();
                }

                inDetails = true;
            }
            else
            {
                reader.Skip();
            }

            reader.Read();
        }
        if (inDetails)
        {
            if (reader.TokenType != JsonToken.EndObject)
            {
                throw new JsonSerializationException();
            }

            reader.Read();
        }

        return result;
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        if (value == null)
        {
            writer.WriteNull();
            return;
        }

        var model = value as MyModel;
        if (model == null) throw new JsonSerializationException();

        writer.WriteStartObject();
        writer.WritePropertyName("name");
        writer.WriteValue(model.Name);
        writer.WritePropertyName("details");
        writer.WriteStartObject();
        writer.WritePropertyName("size");
        serializer.Serialize(writer, model.Size);
        writer.WritePropertyName("weight");
        writer.WriteValue(model.Weight);
        writer.WriteEndObject();
        writer.WriteEndObject();
    }
}

[JsonConverter(typeof(MyModelJsonConverter))]
public class MyModel
{
    public string Name { get; set; }
    public string[] Size { get; set; }
    public string Weight { get; set; }
}

With the attribute on the class, using it is as easy as:

var model = new MyModel
{
    Name = "widget",
    Size = new[] { "XL", "M", "S" },
    Weight = "heavy"
};

string output = JsonConvert.SerializeObject(model);
// {"name":"widget","details":{"size":["XL","M","S"],"weight":"heavy"}}

var model2 = JsonConvert.DeserializeObject(output);
/*
{
    Name = "widget",
    Size = [ "XL", "M", "S" ],
    Weight = "heavy"
}
*/