using System;

using System.Collections.ObjectModel;

​

public class Program

{

    public static void Main(string[] args)

    {

        ObservableCollection<string> list = new ObservableCollection<string>();

        list.CollectionChanged += List_CollectionChanged;

        list.Add("Teste 1");

        list.Add("Teste 2");

    }

    private static void List_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)

    {

        Console.WriteLine("A lista foi alterada.");

    }

}