Implementing .Net ArrayList with Changed event

Sometimes we need a List which can notify user when an item is added. Here is the way that you can implement a generic ArrayList which notifies user at the time of an element is added.

using System; using System.Collections; namespace ArchiveData.Logging {   // A delegate type for hooking up change notifications.   public delegate void ChangedEventHandler(object sender, EventArgs e);   public class ListWithChangedEvent : ArrayList   {     // An event that clients can use to be notified whenever the     // elements of the list change.     public event ChangedEventHandler Changed;     public object NewlyAddedItem { get; set; }     // Invoke the Changed event; called whenever list changes     protected virtual void OnChanged(EventArgs e)     {       if (Changed != null)         Changed(this, e);     }     // Override some of the methods that can change the list;     // invoke event after each     public override int Add(object value)     {       NewlyAddedItem = value;       var i = base.Add(value);       OnChanged(EventArgs.Empty);       return i;     }     public override void Clear()     {       base.Clear();       OnChanged(EventArgs.Empty);     }     public override object this[int index]     {       set       {         base[index] = value;         OnChanged(EventArgs.Empty);       }     }   } }

I got this from MSDN. I feel that it would be helpful to you all too.

Enjoy!