using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Diagnostics;

using System.IO;

​

using Newtonsoft.Json;

​

using System.Xml.Linq;

using System.Xml.Serialization;

using System.Xml;

using System.Xml.Schema;

​

// https://stackoverflow.com/questions/40998611/custom-xml-deserialization-runs-into-an-endless-loop

​

    public class ParentEntity

    {

        public ParentEntity() { Childs = new List<ChildEntity>(); }

        public List<ChildEntity> Childs { get; set; }

    }

​

    public class ChildEntity : IXmlSerializable

    {

        public string Name { get; set; }

​

        public XmlSchema GetSchema()

        {

            return null;

        }

​

        public void ReadXml(XmlReader reader)

        {

            Name = reader.GetAttribute("Name");

            reader.Skip(); // Consume the <ChildEntity> and </ChildEntity> (if present) nodes and everything contained therein.

        }

​

        public void WriteXml(XmlWriter writer)

        {

            writer.WriteAttributeString("Name", Name);

        }

    }

​

    class TestClass

    {

        public static void Test()

        {

            var parent = new ParentEntity { Childs = { new ChildEntity { Name = "hello" }, new ChildEntity { Name = "there" } } };

​

            var xml = parent.GetXml();

​

            Console.WriteLine("Testing round-trip... ");

            var xml2 = Test(parent, xml);

​

            if (xml2 != xml)

            {

                throw new InvalidOperationException("xml2 != xml");

            }

​

            var element = XElement.Parse(xml2);

            element.Elements("Childs").Elements("ChildEntity").ElementAt(1).Add(new XElement("DummyElementThatShouldBeIgnored"));

            var xml3 = element.ToString();

​

            Console.WriteLine("Testing round-trip with dummy child element added that should be ignored... ");

            Test(parent, xml3);

​

            var xml4 = XDocument.Parse(xml).ToString(SaveOptions.DisableFormatting);

​

            Console.WriteLine("Testing round-trip with no formatting... ");

            Test(parent, xml4);

​

            Console.WriteLine("Success.");

        }

​

        private static string Test(ParentEntity parent, string testInputXml)

        {

            Console.WriteLine(testInputXml);

            var newParent = testInputXml.LoadFromXml<ParentEntity>();

            if (JsonConvert.SerializeObject(parent) != JsonConvert.SerializeObject(newParent))

            {

                throw new InvalidOperationException("JsonConvert.SerializeObject(parent) != JsonConvert.SerializeObject(newParent)");

            }

            if (!parent.Childs.Select(c => c.Name).SequenceEqual(newParent.Childs.Select(c => c.Name)))

            {

                throw new InvalidOperationException("!parent.Childs.Select(c => c.Name).SequenceEqual(newParent.Childs.Select(c => c.Name))");

            }

​

            return parent.GetXml();

        }

    }

    public class Program

    {

        public static void Main()

        {

            TestClass.Test();

        }

    }

​

    public static class XmlSerializationHelper

    {

        public static T LoadFromXml<T>(this string xmlString)

        {

            using (StringReader reader = new StringReader(xmlString))

            {

                return (T)new XmlSerializer(typeof(T)).Deserialize(reader);

            }

        }

​

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

                    new XmlSerializer(obj.GetType()).Serialize(xmlWriter, obj, ns);

                return textWriter.ToString();

            }

        }

    }

​