using System;

using System.ComponentModel;

​

public class Program

{

    public static void Main()

    {

        var y = new Y();

        y.MyProperty = 3;

        Console.WriteLine("MyProperty = {0}", y.MyProperty);

        Console.WriteLine("MyPropertyOriginal = {0}", y.MyPropertyOriginal);

        y.MyPropertyOriginal = 4;

        Console.WriteLine("MyProperty = {0}", y.MyProperty);

        Console.WriteLine("MyPropertyOriginal = {0}", y.MyPropertyOriginal);

    }

}

​

public class Y : INotifyPropertyChanged

{

    private object _lock = new object ();

    private int _myPropertyOriginal;

    public int MyPropertyOriginal

    {

        get

        {

            return _myPropertyOriginal;

        }

​

        set

        {

            lock (_lock)

            {

                if (value != _myPropertyOriginal)

                {

                    _myPropertyOriginal = value;

                    if (_myPropertyOriginal != _myProperty)

                        _myProperty = value;

                    NotifyPropertyChanged("MyPropertyOriginal");

                }

            }

        }

    }

​

    private int _myProperty;

    public int MyProperty

    {

        get

        {

            return _myProperty;

        }

​

        set

        {

            lock (_lock)

            {

                //The property changed event will get fired whenever

                //the value changes. The subscriber will do work if the value is

                //1. This way you can keep your business logic outside of the setter

                if (value != _myProperty)

                {

                    _myProperty = value;

                    if (_myPropertyOriginal != _myProperty)

                        _myPropertyOriginal = value;

                    NotifyPropertyChanged("MyProperty");

                }

            }

        }

    }

​

    private void NotifyPropertyChanged(string propertyName)

    {

        if (PropertyChanged != null)

            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));

    }

​

    public event PropertyChangedEventHandler PropertyChanged;

}