Notifying Point List for glinkis

PointList.cs

using System.Collections;
using System.Collections.Generic;

namespace Railmaker
{
    public delegate void ChangedEventHandler(PointList sender, Point item);

    public class PointList : IList<Point>
    {
        private List<Point> points = new List<Point>();

        public event ChangedEventHandler Changed;
        public event ChangedEventHandler Added;
        public event ChangedEventHandler Removed;

        protected void OnChanged(Point item)
        {
            if (Changed != null)
                Changed(this, item);
        }
        
        protected void OnAdded(Point item)
        {
            if (Added != null)
                Added(this, item);
        }
        
        protected void OnRemoved(Point item)
        {
            if (Removed != null)
                Removed(this, item);
        }

        public IEnumerator<Point> GetEnumerator()
        {
            return points.GetEnumerator();
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return points.GetEnumerator();
        }

        public void Add(Point item)
        {
            item.Changed += OnChanged;
            points.Add(item);
            OnAdded(item);
        }

        public void Clear()
        {
            points.Clear();
            OnChanged(); //I dunno....
        }

        public bool Contains(Point item)
        {
            return points.Contains(item);
        }

        public void CopyTo(Point[] array, int arrayIndex)
        {
            points.CopyTo(array, arrayIndex);
        }

        public bool Remove(Point item)
        {
            bool remove = points.Remove(item);
            item.Changed -= OnChanged;
            OnRemoved(item);
            return remove;
        }

        public int Count
        {
            get { return points.Count; }
        }

        public bool IsReadOnly { get; private set; }

        public int IndexOf(Point item)
        {
            return points.IndexOf(item);
        }

        public void Insert(int index, Point item)
        {
            item.Changed += OnChanged;
            points.Insert(index, item);
            OnAdded(item);
        }

        public void RemoveAt(int index)
        {
            var item = points[index];
            points.RemoveAt(index);
            OnRemoved(item);
        }

        public Point this[int index]
        {
            get { return points[index]; }
            set
            {
                points[index] = value;
                OnChanged(value);
            }
        }
    }
}