How to Serialize a Class Derived from List in Json.Net while Preserving Both Custom Properties and List Items?

Json.Net: Serialize Members of a Class Derived from List

Json.Net by default treats classes that implement IEnumerable as arrays. To override this behavior, mark the derived class with [JsonObject] and [JsonProperty] attributes. However, this only serializes the members of the derived class, not the list.

To serialize both the derived class members and the list, provide a public property on the derived class to expose the list:

class PagedResult<T> : List<T>
{
    public IEnumerable<T> Items { get { return this; } }
}

Alternatively, create a custom JsonConverter to serialize the whole thing:

class PagedResultConverter<T> : JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        return (objectType == typeof(PagedResult<T>));
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        PagedResult<T> result = (PagedResult<T>)value;
        JObject jo = new JObject();
        jo.Add("Properties", JObject.FromObject(result, serializer));
        jo.Add("Items", JArray.FromObject(result.ToArray(), serializer));
        jo.WriteTo(writer);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        JObject jo = JObject.Load(reader);
        PagedResult<T> result = new PagedResult<T>();
        jo["Properties"].ToObject<PagedResult<T>>(serializer);
        result.AddRange(jo["Items"].ToObject<T[]>(serializer));
        return result;
    }
}

Register the converter in the JsonSerializerSettings:

JsonSerializerSettings settings = new JsonSerializerSettings();
settings.Converters.Add(new PagedResultConverter<T>());

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