如果所有数据成员都为空，如何在C#中序列化到Json时删除空值

using Newtonsoft.Json;

public class MyClass
{
    public string Name { get; set; }
    public int Age { get; set; }
    public string Address { get; set; }
}

public class Program
{
    public static void Main()
    {
        MyClass obj = new MyClass
        {
            Name = null,
            Age = 25,
            Address = null
        };

        JsonSerializerSettings settings = new JsonSerializerSettings
        {
            NullValueHandling = NullValueHandling.Ignore
        };

        string json = JsonConvert.SerializeObject(obj, settings);
        Console.WriteLine(json);
    }
}

{"Age":25}