using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Xml.Serialization;

using System.Xml;

using System.IO;

using System.Diagnostics;

using System.Collections.ObjectModel;

using System.Threading;

using System.ComponentModel;

using System.Xml.Linq;

using System.Reflection;

using System.Data;

using System.Xml.Schema;

using System.Text.RegularExpressions;

using System.Net;

using System.Xml.XPath;

using System.Globalization; 

using System.ComponentModel.DataAnnotations;

using System.Collections;

using System.Drawing;

​

    // https://stackoverflow.com/questions/40754001/serialize-a-listkeyvaluepairstring-object

​

    public class RootObject

    {

        [XmlIgnore]

        public List<KeyValuePair<string, object>> Items { get; set; }

​

        [XmlAnyElement]

        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never), DebuggerBrowsable(DebuggerBrowsableState.Never)]

        public XElement[] XmlItems

        {

            get

            {

                if (Items == null)

                    return null;

                return Items.Select(p => new XElement(p.Key, (p.Value ?? string.Empty).ToString())).ToArray();

            }

            set

            {

                if (value == null)

                    return;

                Items = Items ?? new List<KeyValuePair<string, object>>(value.Length);

                foreach (var e in value)

                {

                    Items.Add(new KeyValuePair<string, object>(e.Name.LocalName, e.Value));

                }

            }

        }

    }

​

    class TestClass

    {

        public static void Test()

        {

            var root = new RootObject

            {

                Items = new object[]

                {

                    "hello",

                    3.14,

                    3.14m,

                    int.MaxValue,

                    Math.PI,

                    DateTime.Today,

                    System.Drawing.Color.AliceBlue,

                    null,

                    "goodbye",

                }

                .Select((o, i) => new KeyValuePair<string, object>("Key" + i.ToString(), o))

                .ToList(),

            };

            Test(root);

            Test(new RootObject());

        }

​

        private static void Test(RootObject root)

        {

            var xml = root.GetXml(true);

            Console.WriteLine(xml);

            var root2 = xml.LoadFromXML<RootObject>();

            var xml2 = root2.GetXml(true);

            Console.WriteLine(xml2);

​

            if (!XNode.DeepEquals(XElement.Parse(xml), XElement.Parse(xml2)))

            {

                throw new InvalidOperationException("!XNode.DeepEquals(XElement.Parse(xml), XElement.Parse(xml2))");

            }

            else

            {

                Console.WriteLine("Serialized and re-serialized XML look equivalent.");

            }

        }

    }

​

    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();

            }

        }

    }