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;

​

//https://stackoverflow.com/questions/52108420/remove-arrayof-when-serializing-a-listt

​

    public static class XObjectExtensions

    {

        public static XElement SerializeToXElement<T>(this T obj, XContainer parent = null, XmlSerializer serializer = null, XmlSerializerNamespaces ns = null)

        {

            if (obj == null)

                throw new ArgumentNullException();

            // Initially, write to a fresh XDocument to cleanly avoid the exception described in

            // https://stackoverflow.com/questions/19045921/net-xmlserialize-throws-writestartdocument-cannot-be-called-on-writers-created

            var doc = new XDocument();

            using (var writer = doc.CreateWriter())

            {

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

            }

            // Now move to the incoming parent.

            var element = doc.Root;

            if (element != null)

            {

                element.Remove();

                if (parent != null)

                {

                    parent.Add(element);

                }

            }

            return element;

        }

        public static XmlSerializerNamespaces NoStandardXmlNamespaces()

        {

            var ns = new XmlSerializerNamespaces();

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

            return ns;

        }

    }

​

    public class WikiEntry

    {

        public string Id { get; set; }

        public string Title { get; set; }

        public string Content { get; set; }

        [XmlArray]

        public List<Category> Categories { get; set; }

    }

​

    public class Category

    {

        [XmlAttribute]

        public string Id { get; set; }

        [XmlAttribute]

        public string Text { get; set; }

    }

​

    public class TestClass

    {

        public static void Test()

        {

            var initialXml = @"<Wiki>

  <Categories></Categories>

  <Tags></Tags>

  <WikiEntries></WikiEntries>

</Wiki>";

            var xDoc = XDocument.Parse(initialXml);

            Test(xDoc);

            Test(xDoc);

        }

        static void Test(XDocument xDoc)

        {

            WikiEntry wiki = new WikiEntry

            {

               Id = Guid.NewGuid().ToString(),

               Title = "Simple title",

               Content = "Simple content here",

               Categories = new List<Category>

                 {

                   new Category

                   {

                     Id = Guid.NewGuid().ToString(),

                     Text = "SCL"

                   },

                   new Category

                   {

                     Id = Guid.NewGuid().ToString(),

                     Text = "KFL"

                   }

                }

            };

​

            var categories = xDoc.Root.Element("Categories");

            foreach (var category in wiki.Categories)

            {

                category.SerializeToXElement(categories);

            }

​

            Console.WriteLine(xDoc);

        }

    }

​

    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;

            }

        }

    }

​