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/52839645/c-sharp-adding-node-in-xml-error-this-operation-would-create-an-incorrectly-st/52839819#52839645

​

    public class TestClass

    {

        public static void Test()

        {

            XDocument xDoc1 = XDocument.Parse(GetXml1());

​

            XDocument xDoc2 = XDocument.Parse(GetXml2());

​

            //XElement currentTimeNode = xDoc2.Descendants("Time").ToList()[0]; //first decendent

            var currentTimeNode = xDoc2.Descendants("Time").First(); //first decendent

            if (xDoc1.Root == null)

                xDoc1.Add(new XElement("CurrentStatus"));

            xDoc1.Root.AddFirst(currentTimeNode);

            Console.WriteLine(xDoc1);

            XmlAssert.AreEqual(xDoc1.Root, XElement.Parse(GetRequiredXml()));

            Console.WriteLine("\nXML modified as required.");

        }

        static string GetXml1()

        {

            var xml = @"<CurrentStatus>

    <Time Stamp= ""12:30"">

        <price>100</price>

        <amount>1</amount>

    </Time>

​

    <Time Stamp= ""14:50"">

        <price>10</price>

        <amount>5</amount>

    </Time> 

​

    <Time Stamp= ""16:30"">

        <price>10</price>

        <amount>5</amount>

    </Time>     

</CurrentStatus>";

            return xml;

        }

        static string GetXml2()

        {

            var xml = @"<CurrentStatus>

    <Time Stamp= ""17:22"">

        <price>40</price>

        <amount>120</amount>

    </Time>               

</CurrentStatus>";

            return xml;

        }

        static string GetRequiredXml()

        {

            var xml = @"<CurrentStatus>

    <Time Stamp= ""17:22"">

        <price>40</price>

        <amount>120</amount>

    </Time>               

​

    <Time Stamp= ""12:30"">

        <price>100</price>

        <amount>1</amount>

    </Time>

​

    <Time Stamp= ""14:50"">

        <price>10</price>

        <amount>5</amount>

    </Time> 

​

    <Time Stamp= ""16:30"">

        <price>10</price>

        <amount>5</amount>

    </Time>     

</CurrentStatus>

";

            return xml;

        }

    }

    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;

            }

        }

    }

​