C#: Help determining selected node index in a TreeView. NullReferenceException error?
<p>I'm trying to make it so I can run certain events when a node is selected in a TreeView. I run the code and I get an error that reads NullReferenceException was unhandled: Object reference not set to an instance of an object.</p>

<p>Any clues on how to overcome this obstacle?</p>

<pre><code>    private void tvNodes_NodeMouseClick(object sender, TreeNodeMouseClickEventArgs e)
    {
        switch (tvNodes.SelectedNode.Index)
        {
            case 0:
                //first item
                break;

            case 1:
                //second item
                break;

            case 2:
                //third item
                break;
        }
    }
</code></pre>
