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.Runtime.InteropServices;

using System.Runtime.Serialization;

​

    // https://stackoverflow.com/questions/47589607/xml-values-with-same-name-to-list

​

​

    [XmlRoot(ElementName = "DUE")]

    public class DueDTO

    {

        [XmlAttribute(AttributeName = "idx")]

        public string Idx { get; set; }

        [XmlText]

        public string Text { get; set; }

    }

​

    [XmlRoot(ElementName = "RATE")]

    public class RateDTO

    {

        [XmlAttribute(AttributeName = "idx")]

        public string Idx { get; set; }

        [XmlText]

        public decimal Text { get; set; }

    }

​

    [XmlRoot(ElementName = "INVOICE")]

    public partial class InvoicesDTO

    {

        [XmlAttribute(AttributeName = "ID")]

        public string Id { get; set; }

        [XmlElement(ElementName = "STATUS")]

        public string Status { get; set; }

        [XmlElement(ElementName = "TOTAL")]

        public decimal Total { get; set; }

​

        [XmlElement(ElementName = "DUE")]

        public List<DueDTO> Due { get; set; }

        [XmlElement(ElementName = "RATE")]

        public List<RateDTO> Rate { get; set; }

    }

​

    public partial class InvoicesDTO

    {

        public InvoicesDueDates[] InvoicesDueDates

        {

            get

            {

                // To make suure we handle cases where only a Rate or Due item of a specific index is present,

                // perform left outer joins with all indices on both Rate and Due.

                // https://docs.microsoft.com/en-us/dotnet/csharp/linq/perform-left-outer-joins

                var query = from i in Due.Select(d => d.Idx).Concat(Rate.Select(r => r.Idx)).Distinct()

                            join due in Due on i equals due.Idx into dueGroup

                            // Throw an exception if we have more than one due item for a given index

                            let due = dueGroup.SingleOrDefault()

                            join rate in Rate on i equals rate.Idx into rateGroup

                            // Throw an exception if we have more than one rate item for a given index

                            let rate = rateGroup.SingleOrDefault()

                            select new InvoicesDueDates { Id = i, DueDate = due == null ? null : due.Text, Rate = rate == null ? (decimal?)null : rate.Text };

                return query.ToArray();

            }

        }

    }

​

​

    public class InvoicesDueDates

    {

        public string Id { get; set; }

        public string DueDate { get; set; }

        public decimal? Rate { get; set; }

    }

​

    public class RootObjectDTO

    {

        [XmlElement("INVOICE")]

        public List<InvoicesDTO> InvoicesDTO { get; set; }

    }

​

    public class TestClass

    {

        public static void Test()

        {

            var xml = GetXml();

​

            var root = xml.LoadFromXml<RootObjectDTO>();

​

            var xml2 = root.GetXml(true);

​

            Console.WriteLine("\nRe-serialized list of list of all InvoicesDueDates: ");

            Console.WriteLine(root.InvoicesDTO.Select(d => d.InvoicesDueDates).ToArray().GetXml());

​

            Console.WriteLine("\nRe-serialized {0}", root);

            Console.WriteLine(xml2);

        }

​

        static string GetXml()

        {

            var xml = @"<RootObjectDTO>

<INVOICE ID=""4"">

    <STATUS>S</STATUS>

    <TOTAL>6230.00</TOTAL>

    <DUE idx=""1"">14.12.17</DUE>

    <RATE idx=""1"">6230.00</RATE>

</INVOICE >

<INVOICE ID=""5"">

    <STATUS>S</STATUS>

    <TOTAL>3270.00</TOTAL>

    <DUE idx=""1"">30.11.17</DUE>

    <RATE idx=""1"">1090.00</RATE>

    <DUE idx=""2"">07.12.17</DUE>

    <RATE idx=""2"">1090.00</RATE>

    <DUE idx=""3"">14.12.17</DUE>

    <RATE idx=""3"">1090.00</RATE>

</INVOICE>

</RootObjectDTO>";

            return xml;

        }

    }

​

    public class AssertionFailedException : System.Exception

    {

        public AssertionFailedException() : base() { }

​

        public AssertionFailedException(string s) : base(s) { }

    }

​

    public static class Assert

    {

        public static void IsTrue(bool value)

        {

            IsTrue(value, "failed");

        }

​

        public static void IsTrue(bool value, string message)

        {

            if (value == false)

                throw new AssertionFailedException(message ?? "failed");

        }

    }

​

    public static class XmlSerializationHelper

    {

        public static T LoadFromXml<T>(this string xmlString, XmlSerializer serial = null)

        {

            serial = serial ?? new XmlSerializer(typeof(T));

            T returnValue = default(T);

            using (StringReader reader = new StringReader(xmlString))

            {

                object result = serial.Deserialize(reader);

                if (result is T)

                {

                    returnValue = (T)result;

                }

            }

            return returnValue;

        }

​

        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 class Program

    {

        public static void Main()

        {

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

            Console.WriteLine();

​

            TestClass.Test();

        }

    }

​