Why is my "Event" always null?
<p>I am trying to wire up a new event, but for some reason "Changed" is always evaluating to null</p>

<pre><code>    public class MyTreeViewItem : INotifyPropertyChanged

{
        private MyTreeViewItem _parent;

        public MyTreeViewItem(MyTreeViewItem parent)
        {
            _parent = parent;
        }

        private bool _checked;
        public bool Checked
        {
            get
            {
                return _checked;
            }
            set
            {
                if (value != _checked)
                {
                    _checked = value;
                    OnChanged("test");
                    OnPropertyChanged("Checked");
                }
            }
        }

        public event EventHandler Changed;

        public ObservableCollection&lt;MyTreeViewItem&gt; Children { get; set; }

    // Invoke the Changed event; called whenever list changes
    protected virtual void OnChanged(string test)
    {
        if (Changed != null)
            Changed(this, null);
    }
</code></pre>

<p><strong>Subscribing code (PropertyChanged Works, Changed does not)</strong></p>

<pre><code>_playgroupTree = new MyTreeViewItem(null);
AddChildNodes(4, ref _playgroupTree);
_playgroupTree.Changed += new EventHandler(_playgroupTree_Changed);
_playgroupTree.PropertyChanged += new PropertyChangedEventHandler(_playgroupTree_PropertyChanged);
</code></pre>

<p>Is really weird because I am also implementing INotifyPropertyChanged (which works), and this code is almost exactly the same (I have tried using the same deligate type, but still it does not work.</p>

<p>I have been using this website as a reference
<a href="http://msdn.microsoft.com/en-us/library/aa645739%28VS.71%29.aspx" rel="nofollow">http://msdn.microsoft.com/en-us/library/aa645739%28VS.71%29.aspx</a></p>
