Check a IList changed?
<p>I am trying to make an appointment book in Silverlight with C#, so I will have a main <code>AppointmentBook</code> control, with follows to store each of the <code>Appointment</code> control:</p>

<pre><code>    List&lt;kAppointment&gt; appointments = null;

    public IList&lt;kAppointment&gt; Appointments
    {
        get
        {
            if (appointments == null)
            {
                appointments = new List&lt;kAppointment&gt;();
            }

            // Can notify something change here, 
            return appointments;
        }
    }
</code></pre>

<p>I can notify the <code>AppointmentBook</code> control new list assigned with above code, so it will redraw each of the appointments control.</p>

<p>But how can I check it if the appointment list is changed by the follows?:</p>

<pre><code>appointments.Add(NewAppointment);
</code></pre>
