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/58331559/could-jsondocument-be-used-as-contractresolver

​

    public class TestClass

    {

        public static void Test()

        {

            XNamespace fooNs = "http://www.example.com/xmlns/foo-version1";

            XNamespace defNs = "http://www.example.com/xmlns";

            var root = new XElement(fooNs + "document"

                                    // Add the namespace declarations with your desired prefixes.  Be sure to pass them into the constructor.

                                    , new XAttribute("xmlns", defNs.ToString())

                                    , new XAttribute(XNamespace.Xmlns + "foo", fooNs.ToString())

                                    // And add any required content.  The content can be passed into the constructor, or added later. 

                                    , new XElement(fooNs + "bar", new XAttribute(fooNs + "baz", true)));

            var xml = root.ToString();

​

            Console.WriteLine(xml);

            Assert.IsTrue(XNode.DeepEquals(XElement.Parse(xml), XElement.Parse(GetRequiredXml())));

        }

        static string GetRequiredXml()

        {

            return @"<foo:document xmlns=""http://www.example.com/xmlns"" xmlns:foo=""http://www.example.com/xmlns/foo-version1"">

    <foo:bar foo:baz=""true"" />

</foo:document>";

        }

    }

​

    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;

        }

    }

​