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.Text.Json;

​

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

​

#nullable enable

​

//https://stackoverflow.com/questions/76950645/c-sharp-deserialize-known-unknownelement-from-xml

​

    public class TestClass

    {

        public static void Test()

        {

            var s = "I'm from Foo.A";

            Console.WriteLine(s.GetXml(omitStandardNamespaces : true));

        }

    }

​

    public static partial class XmlExtensions

    {

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

        {

            serial = serial ?? new XmlSerializer(typeof(T));

            using (var reader = new StringReader(xmlString))

            {

                return (T?)serial.Deserialize(reader);

            }

        }

​

        public static string GetXml<T>(this T obj, bool omitStandardNamespaces)

        {

            return obj.GetXml(null, omitStandardNamespaces);

        }

        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() ?? typeof(T))).Serialize(xmlWriter, obj, ns);

                return textWriter.ToString();

            }

        }

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: {0} ({1}, {2})", System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription , Environment.Version, Environment.OSVersion);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

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

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​