// @nuget: Newtonsoft.Json

​

using System;

using:

public class Test

{

    public int test_int {get;set;}

    public string test_string {get;set;}

}

​

public class Program

{

    public static void Main()

    {

        Test test1 = new Test{ test_int = 1, test_string = null};

        var settings =  new JsonSerializerSettings {

            NullValueHandling = NullValueHandling.Ignore};

        var test1str = JsonConvert.SerializeObject(test1, settings);        

        Console.WriteLine(test1str);

        var test2str = test1.GetType().GetProperty("test_int").GetValue(test1); 

        Console.WriteLine(test2str);

    }

}