C#

        private System.Windows.Forms.ListBox listBox1;<br />
        private System.Windows.Forms.Button button1;<br />
<br />
        // ItemList shall contain the content for the ListBox<br />
         private ItemList itemList = null;<br />
<br />
         public Form1()<br />
         {<br />
            InitializeComponent();<br />
<br />
            itemList = new ItemList();<br />
<br />
            itemList.Add(new Item(1,"One"));<br />
            itemList.Add(new Item(2,"Two"));<br />
            itemList.Add(new Item(3,"Three"));<br />
<br />
            listBox1.DataSource = itemList;<br />
            listBox1.DisplayMember = "Desc";<br />
<br />
            itemList.eventHandler<br />
                += new EventHandler(listBox1_DataSourceChanged);<br />
        }<br />
<br />
        // Is called, when ItemList has changes<br />
        private void listBox1_DataSourceChanged(<br />
            object sender, System.EventArgs e)<br />
        {<br />
            Console.Out.WriteLine("DataSource changed 2");<br />
<br />
            // try all ways to update the list...<br />
            listBox1.Refresh();  // no effect<br />
            Rectangle rect = new Rectangle(new Point(0,0),listBox1.Size);<br />
            listBox1.Invalidate(rect,true); // no effect<br />
            listBox1.Update(); // no effect<br />
        }

   public class Item<br />
    {<br />
        private int nr;<br />
        private string name;<br />
<br />
        public Item(int a, string b)<br />
        {<br />
            nr = a;<br />
            name = b;<br />
        }<br />
<br />
        public string Desc { get { return "Nr:" + nr + " Name=" + name; } }<br />
   }<br />

     public class ItemList : ArrayList<br />
     {<br />
        public EventHandler eventHandler = null;<br />
<br />
        public ItemList()<br />
        {<br />
        }<br />
<br />
        public void Remove(Item item)<br />
        {<br />
            Console.Out.WriteLine("Soll loeschen: " + item.Desc);<br />
            base.Remove(item);<br />
            FireDataChanged();<br />
        }<br />
<br />
        public void Add(Item item)<br />
        {<br />
            Console.Out.WriteLine("Soll adden: " + item.Desc);<br />
            base.Add(item);<br />
            FireDataChanged();<br />
        }<br />
<br />
        private void FireDataChanged()<br />
        {<br />
<br />
            if (eventHandler != null)<br />
            {<br />
                eventHandler(this,null);<br />
            }<br />
        }<br />
     }