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/55914228/how-do-i-declare-a-xdocument-namespace-globally-in-c

​

    public static class XObjectExtensions

    {

        public static XElement CreateAndAddInRootDefaultNamespace(this XElement parent, string localName)

        {

            if (parent == null)

                throw new ArgumentNullException();

            // Get the topmost parent as an XDocument

            // https://referencesource.microsoft.com/#System.Xml.Linq/System/Xml/Linq/XLinq.cs,956

            var doc = parent.Document;

            if (doc == null || doc.Root == null)

                throw new ArgumentException(string.Format("No root element found for {0}", parent.Name));

            var element = new XElement(doc.Root.GetDefaultNamespace() + localName);

            parent.Add(element);

            return element;

        }

    }

​

    public class TestClass

    {

        public static void Test()

        {

            var xdoc = XDocument.Parse(GetXml());

            xdoc.Root.CreateAndAddInRootDefaultNamespace("element");

            xdoc.Root.CreateAndAddInRootDefaultNamespace("anotherElement")

                .CreateAndAddInRootDefaultNamespace("someNestedElement")

                .Add("Some text content");

            Console.WriteLine(xdoc);

        }

        static string GetXml()

        {

            var xml = @"<root xmlns=""https://stackoverflow.com/questions/55914228/how-do-i-declare-a-xdocument-namespace-globally-in-c"" attr1=""attribute one"" attr2=""attribute two"">

    <title>this is the root</title>

    <xhtml>

        <div id=""wrapper"">

            <p style=""first""><em>hello</em> world!</p>

        </div>

    </xhtml>

</root>

";

            return xml;

        }

    }

​

    public static class XmlSerializationHelper

    {

        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())).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 static class XmlAssert

    {

        // https://weblogs.asp.net/marianor/easy-way-to-compare-two-xmls-for-equality

        // https://stackoverflow.com/questions/7318157/best-way-to-compare-xelement-objects

        // Adapted from the answer https://stackoverflow.com/a/14463137 by https://stackoverflow.com/users/1102100/robjohnson

        public static void AreEqual(

            XElement expected,

            XElement actual)

        {

            Assert.IsTrue(XNode.DeepEquals(Normalize(expected), Normalize(actual)));

        }

​

        private static XElement Normalize(XElement element)

        {

            if (element.HasElements)

            {

                return new XElement(

                    element.Name,

                    element.Attributes()

                           .OrderBy(a => a.Name.ToString()),

                    element.Elements()

                           .OrderBy(a => a.Name.ToString())

                           .Select(e => Normalize(e)));

​

            }

​

            if (element.IsEmpty)

            {

                return new XElement(

                    element.Name,

                    element.Attributes()

                           .OrderBy(a => a.Name.ToString()));

            }

​

            return new XElement(element.Name, element.Attributes()

                .OrderBy(a => a.Name.ToString()), element.Value);

        }

    }

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Roslyn 2.0 Compiler; Environment version: " + Environment.Version);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Uncaught exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​