using System;

using System.Collections.Generic;

using System.ComponentModel;

​

namespace ConsoleApplication4

{

  public static class Program

  {

    public static void Main()

    {

      var person = new Person();

      person.PropertyChanged += PersonChanged;

      person.First = "Mike";

      person.First = "Howard";

      person.First = "Bob";

      person.First = "Bob";

    }

​

    private static void PersonChanged( object s, PropertyChangedEventArgs e )

    {

      Person p = (Person)s;

      if (e.PropertyName == "First")

        Console.WriteLine( "{0} CHANGED TO {1}", e.PropertyName, p.First );

      else if(e.PropertyName == "Last")

        Console.WriteLine( "{0} CHANGED TO {1}", e.PropertyName, p.Last );

​

    }

  }

​

  public class Person : Notifier

  {

    private string _first;

    private string _last;

​

    public string First

    {

      get { return _first; }

      set { SetField( ref _first, value, "First" ); }

    }

​

    public string Last

    {

      get { return _last; }

      set { SetField( ref _last, value, "First" ); }

    }

  }

​

  public class Notifier : INotifyPropertyChanged

  {

      public event PropertyChangedEventHandler PropertyChanged = delegate{};

​

    protected bool SetField<T>( ref T field, T value, string propertyName )

    {

      if ( EqualityComparer<T>.Default.Equals( field, value ) )

        return false;

​

      field = value;

      OnPropertyChanged( propertyName );

​

      return true;

    }

​

    private void OnPropertyChanged( string propertyName )

    {

      PropertyChanged.Invoke( this, new PropertyChangedEventArgs( propertyName ) );

    }

  }

}

​