how can i check ObservableCollection's "CollectionChanged" event is null or not
<p>In ObservableCollection how can i check CollectionChanged event is null or not, 
This statement throws syntax error</p>

<pre><code> if (studentList.CollectionChanged == null)
</code></pre>

<p>ErrorMessage:</p>

<p>The event 'System.Collections.ObjectModel.ObservableCollection.CollectionChanged' can only appear on the left hand side of += or -=</p>

<p>Sample Code:</p>

<pre><code> public class School
    {
        public School()
        {
            studentList = new ObservableCollection&lt;Student&gt;();            
            //only when studentList.CollectionChanged is empty i want 
            // to execute the below statement
            studentList.CollectionChanged += Collection_CollectionChanged;
        }
        public ObservableCollection&lt;Student&gt; studentList { get; set; }
  }
</code></pre>
