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 System.Reflection;

​

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

​

    // https://stackoverflow.com/questions/65397664/can-you-deserialize-and-older-version-of-xml-into-a-newer-structure

​

    public interface IUnknownElementHandler

    {

        void OnUnknownElement(object sender, XmlElementEventArgs e);

    }

​

    public static partial class XmlSerializationHelper

    {

        public static T LoadFromXml<T>(this string xmlString, XmlSerializer serializer = null)

        {

            serializer = serializer ?? new XmlSerializer(typeof(T)).AddUnknownElementHandler();

            using (var reader = new StringReader(xmlString))

                return (T)serializer.Deserialize(reader);

        }

​

        public static T LoadFromFile<T>(string filename, XmlSerializer serializer = null)

        {

            serializer = serializer ?? new XmlSerializer(typeof(T)).AddUnknownElementHandler();

            using (var reader = new FileStream(filename, FileMode.Open))

                return (T)serializer.Deserialize(reader);

        }

        public static XmlSerializer AddUnknownElementHandler(this XmlSerializer serializer)

        {

            serializer.UnknownElement += (o, e) =>

            {

                var handler = e.ObjectBeingDeserialized as IUnknownElementHandler;

                if (handler != null)

                    handler.OnUnknownElement(o, e);

            };

            return serializer;

        }

    }

​

    public partial class ContainerType : IUnknownElementHandler

    {

        #region IUnknownElementHandler Members

​

        void IUnknownElementHandler.OnUnknownElement(object sender, XmlElementEventArgs e)

        {

            var container = (ContainerType)e.ObjectBeingDeserialized;

            var element1 = e.Element.SelectSingleNode("element1");

            var element2 = e.Element.SelectSingleNode("element2");

            if (element1 != null || element2 != null)

            {

                container.Objinfo = container.Objinfo ?? new Objinfo();

                if (element1 != null)

                    container.Objinfo.Element1 = element1.InnerText;

                if (element2 != null)

                    container.Objinfo.Element2 = element2.InnerText;

            }

            var element3 = e.Element.SelectSingleNode("element3");

            var element4 = e.Element.SelectSingleNode("element4");

            if (element3 != null || element4 != null)

            {

                container.Newobject = container.Newobject ?? new Newobject();

                if (element3 != null)

                    container.Newobject.Element3 = element3.InnerText;

                if (element4 != null)

                    container.Newobject.Element4 = element4.InnerText;

            }

        }

​

        #endregion

    }

​

    [XmlRoot(ElementName = "Root")]

    public class Root

    {

        public ContainerType ContainerType { get; set; }

    }

    [XmlRoot(ElementName = "ContainerType")]

    public partial class ContainerType 

    {

        [XmlElement(ElementName = "objinfo")]

        public Objinfo Objinfo { get; set; }

        [XmlElement(ElementName = "newobject")]

        public Newobject Newobject { get; set; }

    }

​

    [XmlRoot(ElementName = "objinfo")]

    public class Objinfo

    {

        [XmlElement(ElementName = "element1")]

        public string Element1 { get; set; }

        [XmlElement(ElementName = "element2")]

        public string Element2 { get; set; }

    }

​

    [XmlRoot(ElementName = "newobject")]

    public class Newobject

    {

        [XmlElement(ElementName = "element3")]

        public string Element3 { get; set; }

        [XmlElement(ElementName = "element4")]

        public string Element4 { get; set; }

    }

​

    public class TestClass

    {

        public static void Test()

        {

            var filename = @"Question65397664.xml";

​

            try

            {

                File.WriteAllText(filename, GetOldXml());

                var root = XmlSerializationHelper.LoadFromFile<Root>(filename);

                Console.WriteLine("Deserialized {0} and re-serialized with following XML:");

                Console.WriteLine(root.GetXml());

            }

            finally

            {

                File.Delete(filename);

            }

        }

​

        static string GetOldXml()

        {

            return @"<Root><ContainerType><objectinfo>

<element1>old1</element1>

<element2>old2</element2>

<element3>old3</element3>

<element4>old4</element4>

</objectinfo>

</ContainerType></Root>";

        }

    }

​

    public static partial class XmlSerializationHelper

    {

        public static string GetXml<T>(this T obj, XmlSerializer serializer = null, bool omitStandardNamespaces = false)

        {

            XmlSerializerNamespaces ns = null;

            if (omitStandardNamespaces)

            {

                ns = new XmlSerializerNamespaces();

                ns.Add("", ""); // Disable the xmlns:xsi and xmlns:xsd lines.

            }           

            using (var textWriter = new StringWriter())

            {

                var settings = new XmlWriterSettings() { Indent = true }; // For cosmetic purposes.

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

                    (serializer ?? new XmlSerializer(obj.GetType())).Serialize(xmlWriter, obj, ns);

                return textWriter.ToString();

            }

        }

        public static string GetOuterXml(this XmlNode node, bool indent = true)

        {

            if (node == null)

                return null;

            using (var textWriter = new StringWriter())

            {

                var settings = new XmlWriterSettings

                {

                    Indent = indent,

                    OmitXmlDeclaration = true,

                };

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

                {

                    node.WriteTo(xmlWriter);

                }

                return textWriter.ToString();

            }

        }

    }

​

    public class Program

    {

        public static void Main()

        {

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

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

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

                Console.WriteLine(ex);

                throw;

            }

        }

        public static string GetNetCoreVersion()

        {

            //https://techblog.dorogin.com/how-to-detect-net-core-version-in-runtime-ecd65ad695be

            //

            var assembly = typeof(System.Runtime.GCSettings).GetTypeInfo().Assembly;

            var assemblyPath = assembly.CodeBase.Split(new[] { '/', '\\' }, StringSplitOptions.RemoveEmptyEntries);

            int netCoreAppIndex = Array.IndexOf(assemblyPath, "Microsoft.NETCore.App");

            if (netCoreAppIndex > 0 && netCoreAppIndex < assemblyPath.Length - 2)

                return assemblyPath[netCoreAppIndex + 1];

            return null;

        }

    }

​