using System;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        Uri uri = new Uri("http://www.test.de");

        string json = JsonConvert.SerializeObject(uri);

        Console.WriteLine(json);

        TestObject testObject = new TestObject();

        testObject.test1 = "test1";

        testObject.test2 = new Uri("urn:meditrac:bla");

        string json2 = JsonConvert.SerializeObject(testObject);

        Console.WriteLine(json2);

    }

}

​

public class TestObject

{

    public string test1 { get; set; }

    public Uri test2 { get; set; }

}