using System;

using System.Collections.Generic;

using System.Text;

using System.Linq;

using System.Xml.Serialization;

using System.Xml;

using System.Xml.Linq;

using System.IO;

using System.Data;

using System.Runtime.Serialization;

using System.Runtime.Serialization.Formatters.Binary;

using System.IO.Compression;

​

using NUnit.Framework; //NUnit.Framework.AssertionException

​

//https://stackoverflow.com/questions/71942443/why-interface-type-members-are-interpreted-as-the-enclosing-interface-while-crea

​

    public interface ITest

    {

        public sealed class Test //: ITest

        {

            public string TestString { get; set; }

        }

​

        string TestString { get; }

    }

​

    public sealed class Test : ITest

    {

        public string TestString { get; set; }

    }

    public class TestClass

    {

        public static void Test()

        {

            var serializer1 = new XmlSerializer(typeof(Test));

            Console.WriteLine($"{nameof(serializer1)} created.");

            var test = new ITest.Test { TestString = "Test String" };

            var xml = test.ToContractXml();

            var test2 = DataContractSerializerHelper.FromContractXml<ITest.Test>(xml);

            Console.WriteLine($"{test2} round-tripped successfully by DataContractSerializer:\n{xml}");

            var serializer2 = new XmlSerializer(typeof(ITest.Test));

            Console.WriteLine($"{nameof(serializer2)} created.");           

        }

    }

​

    public static partial class DataContractSerializerHelper

    {

        public static string ToContractXml<T>(this T obj, DataContractSerializer serializer = null, XmlWriterSettings settings = null)

        {

            serializer = serializer ?? new DataContractSerializer(obj == null ? typeof(T) : obj.GetType());

            using (var textWriter = new StringWriter())

            {

                settings = settings ?? new XmlWriterSettings { Indent = true };

                using (var xmlWriter = XmlWriter.Create(textWriter, settings))

                {

                    serializer.WriteObject(xmlWriter, obj);

                }

                return textWriter.ToString();

            }

        }

​

        public static T FromContractXml<T>(string xml, DataContractSerializer serializer = null)

        {

            using (var textReader = new StringReader(xml ?? ""))

            using (var xmlReader = XmlReader.Create(textReader))

            {

                return (T)(serializer ?? new DataContractSerializer(typeof(T))).ReadObject(xmlReader);

            }

        }

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: {0} ({1})", System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription , Environment.Version);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Failed with unhandled exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​