http://samueleresca.net/2015/03/conditional-serialization-using-csharp/

conditional_serialization\serializer.cs

[TestClass]
    public class ConditionalSerializingTests
    {

        public  Telefilm[] Telefilms = new Telefilm[]{

            new Telefilm{TelefilmId=1 , TelefilmName="Slevin" , CreateDate= new DateTime(1999,04,23)},
            new Telefilm{TelefilmId=2 , TelefilmName="Scrubs" , CreateDate= new DateTime(2001,02,08) },
            new Telefilm{TelefilmId=3 , TelefilmName="HIMYM" , CreateDate= new DateTime(2004,12,05)},
            new Telefilm{TelefilmId=4 , TelefilmName="Californication", CreateDate= new DateTime(2010,02,12)}

        };


        [TestMethod]
        public void SerializeTelefilms()
        {

            string serializedObj = JsonConvert.SerializeObject(this.Telefilms, Formatting.Indented);
            serializedObj.ToString();

        }
    }