read XML , sort on attribute and write to text file c#

Question

as beginner in c# : I googled around but got lost in a "simple question" :

Read a XML : 

    <persons>        this is sample 
      <person id="0">
        <Lname>Johnson</Lname>
        <Fname>Molly</Fname>
      </person>
      <person id="1">
        <Lname>buffalo</Lname>
        <Fname>Mike</Fname>
      </person>
      <person id="2">
        <Lname>COOLS</Lname>
        <Fname>WALTER</Fname>
      </person>
      <person id="3">
        <Lname>FROMUS</Lname>
        <Fname>LUDOVICUS</Fname>
    </persons>

I need to sort on Lname (last name) and Fname (first name)
and list up in a text file (txt) to have

E.G. yo see 2 people have Lname of York so then sort on Fname.

 Case John
 Buffalo Mike
 York Theo
 York Viviane

Lname and Fname should be on same line but take a new line for next Lname , Fname.
thats not in this question because of syntax problems here in this tool (sorry)

Additional info : I tried to use foreach with var instruction to list up but got messed. Target is to use e.g LINQ and OO (object oriented ) as much as possible .

thanks a lot

My response to the comments :

---

First I want to apologize for the badformed XML -the last tag had a wrong / symbol. The language was indeed dutch (Netherlands) - I changed tag names into english.

What I already have is reading of XML file and sorting on attribute "id" and write into a flat file. Then I tried to make it more OO by exercising the "foreach var constructions using orderedby .

Code I have now :

using System;
using System.Collections.Generic;
using System.Xml.Linq;
using System.Text;
using System.Threading.Tasks;
using System.ComponentModel;
using System.Data;
using System.IO;
using System.Xml;
using System.Net;

namespace ConsoleApplication3
{
    class Program
    {
        static void Main(string[] args)
        {

       XmlReader reader = XmlReader.Create("c:/download/test.xml");

            List<string> Collectperson = new List<string>();
            Collectperson.Clear();

            string personid = "";
            string nm = "";
            string vn = "";
            string oneline = "";
            while (reader.Read())
            {

                if (reader.NodeType != XmlNodeType.EndElement)
                {

                    // Get element name and switch on it.
                    switch (reader.Name)
                    {
                        case "persoon":
                            // Detect this element.
                            // initialize collectperson 
                            Collectperson.Clear();

                            Console.WriteLine(" " + reader.GetAttribute(0));
                            Collectperson.Add(reader.GetAttribute(0));
                            //   add to  file ans reinitialize string 
                            oneline = "";
                            oneline = string.Join(" ", Collectperson.ToArray());

                            break;
                        //
                        case "naam":
                            if (reader.Read())
                            {
                                Console.WriteLine(reader.Value);
                                nm = reader.Value;
                                Collectperson.Add(nm);
                                oneline = string.Join(" ", Collectperson.ToArray());

                            }
                            break;

                        case "voornaam":
                            if (reader.Read())
                            {
                                Console.WriteLine(reader.Value);
                                vn = reader.Value;
                                Collectperson.Add(vn);
                                oneline = string.Join(" ", Collectperson.ToArray());

         // ==================================================================================
                                string path = @"c:/download/personen.txt";
                                // This text is added only once to the file. 
                                if (!File.Exists(path))
                                {
                                    // Create a file to write to. 
                                    using (StreamWriter sw = File.CreateText(path))
                                    {
                                        sw.WriteLine(oneline);
                                    }
                                }

                                // This text is always added, making the file longer over time 
                                // if it is not deleted. 
                                using (StreamWriter sw = File.AppendText(path))
                                {
                                    sw.WriteLine(oneline);
                                }

        //==================================================================================

                            }
                            break;
                    }  // switch
                }
            }  // while 
        }
    }
}

Answer 1

To load xml file into your model, you can use XmlSerializer.Deserialize

using (var sw = new StreamReader(iPathToXMLFile, Encoding.Default))
{
    var ser = new XmlSerializer(typeof(T));
    val = (T)ser.Deserialize(sw);
}

THen, you can create a class for "person" object and then implement IComparable to be able to sort a list of person :) For example : How do I sort an array of custom classes?

[EDIT1]

Another way :

public class Person
{
    public String FirstName { get; set; }
    public String LastName { get; set; }
}

var list = new List<Person>
{
    new Person {FirstName = "Viviane", LastName = "York"},
    new Person {FirstName = "Mike", LastName = "Buffalo"},
    new Person {FirstName = "Theo", LastName = "York"},
    new Person {FirstName = "John", LastName = "Case"}
};

var sorted = list.OrderBy( p => p.LastName).ThenBy( p => p.FirstName).ToList();

[EDIT2] : IComparable solution

public class Person : IComparable<Person>
{
    public String FirstName { get; set; }
    public String LastName { get; set; }

    public int CompareTo(Person obj)
    {
        var val = String.Compare(LastName, obj.LastName, StringComparison.Ordinal);

        // Same LastName case
        if (0 == val)
            val = String.Compare(FirstName, obj.FirstName, StringComparison.Ordinal);

        return val;
    }
}

        var list = new List<Person>
        {
             new Person {FirstName = "Viviane", LastName = "York"},
            new Person {FirstName = "Mike", LastName = "Buffalo"},
            new Person {FirstName = "Theo", LastName = "York"},
            new Person {FirstName = "John", LastName = "Case"}
        };


        list.Sort(); // Sort will call IComparable implementation of the Person class

[EDIT3]

You can also use IComparer, delegates... I let you search the web for this.

Answer 2

This video may help you out. He explains using XML first and then Json. I prefer Json, and you might also after watching this. Bob Tabor explains things very well. Hope this steers you on the right track.

<<Storing and retrieving Serialized Data>>