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CSharp · Console

/Program.cs

using System;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
					
public class Program
{
	public static void Main()
	{
		var obj1 = new A(4, true);
		var obj2 = new B("hello world");
		
		var json1 = JObject.FromObject(obj1);
		var json2 = JObject.FromObject(obj2);
		json1.Merge(json2);
		
		Console.WriteLine(json1.ToString());
	}
}

public class A
{
    public A(int x, bool y)
    {
        X = x;
        Y = y;
    }

    [JsonProperty("x_thing")]
    public int X { get; }

    [JsonProperty("y_thing")]
    public bool Y { get; }
}

public class B
{
    public B(string s)
    {
        S = s;
    }

    [JsonProperty("string_thing")]
    public string S { get; }
}