using System;

using System.Collections.Generic;

using System.Collections.ObjectModel;

using System.Collections.Specialized;

using System.Linq;

​

public static class Program

{

    static int totalNumOfChangeNotifications = 0;

    static ObservableCollection<Person> observable;

​

    public static void Main()

    {

        Console.WriteLine("\nsorting items...");

​

        Populate();

        observable.AndrewSort();

        Console.WriteLine("AndrewSort: " + totalNumOfChangeNotifications);

​

        Populate();

        observable.AndrewMoveSort();

        Console.WriteLine("AndrewMoveSort: " + totalNumOfChangeNotifications);

​

        Populate();

        observable.TopVotedSort();

        Console.WriteLine("TopVotedSort: " + totalNumOfChangeNotifications);

​

        Populate();

        observable.MySort();

        Console.WriteLine("MySort: " + totalNumOfChangeNotifications);

​

        Console.ReadLine();

    }

​

    static void Populate()

    {

        totalNumOfChangeNotifications = 0;

        observable = new ObservableCollection<Person>

        {

            new Person(){ Id = 0, Name = "A" },

            new Person(){ Id = 3, Name = "C" },

            new Person(){ Id = 2, Name = "B" },

            new Person(){ Id = 3, Name = "C" },

            new Person(){ Id = 3, Name = "C" },

            new Person(){ Id = 1, Name = "A" },

            new Person(){ Id = 3, Name = "C" },

            new Person(){ Id = 3, Name = "C" },

            new Person(){ Id = 3, Name = "C" },

            new Person(){ Id = 3, Name = "C" },

            new Person(){ Id = 2, Name = "A" },

            new Person(){ Id = 3, Name = "C" },

            new Person(){ Id = 3, Name = "C" },

            new Person(){ Id = 3, Name = "C" },

            new Person(){ Id = 3, Name = "C" },

            new Person(){ Id = 3, Name = "A" },

        };

        observable.CollectionChanged += CollectionChangedEventHandler;

    }

​

    static void CollectionChangedEventHandler(object sender, NotifyCollectionChangedEventArgs e)

    {

        totalNumOfChangeNotifications++;

        Console.WriteLine("Type of change: " + e.Action);

    }

​

    public static void AndrewSort<T>(this ObservableCollection<T> collection) where T : IComparable<T>

    {

        List<T> sorted = collection.OrderBy(x => x).ToList();

​

        int ptr = 0;

        while (ptr < sorted.Count)

        {

            if (!collection[ptr].Equals(sorted[ptr]))

            {

                T t = collection[ptr];

                collection.RemoveAt(ptr);

                collection.Insert(sorted.IndexOf(t), t);

            }

            else

            {

                ptr++;

            }

        }

    }

​

    public static void AndrewMoveSort<T>(this ObservableCollection<T> collection) where T : IComparable<T>

    {

        List<T> sorted = collection.OrderBy(x => x).ToList();

​

        int ptr = 0;

        while (ptr < sorted.Count)

        {

            if (!collection[ptr].Equals(sorted[ptr]))

            {

                T t = collection[ptr];

                collection.Move(ptr, sorted.IndexOf(t));

            }

            else

            {

                ptr++;

            }

        }

    }

​

    public static void TopVotedSort<T>(this ObservableCollection<T> collection) where T : IComparable<T>

    {

        List<T> sorted = collection.OrderBy(x => x).ToList();

        for (int i = 0; i < sorted.Count(); i++)

            collection.Move(collection.IndexOf(sorted[i]), i);

    }

​

    public static void MySort<T>(this ObservableCollection<T> collection) where T : IComparable<T>

    {

        int i = 0;

        foreach (T item in collection.OrderBy(x => x))

        {

            int oldIndex = collection.IndexOf(item);

            int newIndex = i++;

            if (oldIndex != newIndex)

                collection.Move(oldIndex, newIndex);

        }

    }

}

​

public class Person : IComparable<Person>, IEquatable<Person>

{

    public string Name { get; set; }

​

    public int Id { get; set; }

​

    public int Age { get; set; }

​

    public int CompareTo(Person other)

    {

        return this.Name.CompareTo(other.Name);

    }

​

    public override string ToString()

    {

        return Name + " aged " + Age + " and Id = " + Id;

    }

​

    public bool Equals(Person other)

    {

        if (ReferenceEquals(null, other)) return false;

        if (ReferenceEquals(this, other)) return true;

        return Name == other.Name;

    }

​

    public override bool Equals(object obj)

    {

        if (ReferenceEquals(null, obj)) return false;

        if (ReferenceEquals(this, obj)) return true;

        if (obj.GetType() != this.GetType()) return false;

        return Equals((Person)obj);

    }

​

    public override int GetHashCode()

    {

        return (Name != null ? Name.GetHashCode() : 0);

    }

}