using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using System;

using System.Collections.Generic;

​

// https://stackoverflow.com/a/44453102/4295017

​

public class Program

{

    public static void Main()

    {

        var json1 = @"{

'test': {

    'object_array1': [

        100

    ],

    'object_array2': [

        'desc'

    ]

}

}";

        var json2 = @"{

'test': [

​

]

}";

        var obj1 = JsonConvert.DeserializeObject<Root>(json1);

        var obj2 = JsonConvert.DeserializeObject<Root>(json2);

        Console.WriteLine("test is defined: {0}\n", JsonConvert.SerializeObject(obj1));

        Console.WriteLine("test is EMPTY: {0}\n", JsonConvert.SerializeObject(obj2));

    }

}

​

public class TestIgnoreEmptyListConverter : JsonConverter

{

    public override bool CanConvert(Type objectType)

    {

        return typeof(Test).IsAssignableFrom(objectType) || objectType.IsArray;

    }

​

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)

    {

        var token = JToken.Load(reader);

        if (token is JArray)

            return default(Test);

        else

            return token.ToObject<Test>();

    }

​

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)

    {

        JObject.FromObject(value).WriteTo(writer);

        // N.B. This is only required for this particular demo. If no serialization is expected

        // for the Root type in your code, you may just leave the line below uncommented

        //throw new NotImplementedException();

    }

}

​

public class Root

{

    [JsonConverter(typeof(TestIgnoreEmptyListConverter))]

    public Test test { get; set; }

}

​

public class Test

{

    public List<int> object_array1 { get; set; }

    public List<string> object_array2 { get; set; }

}

​