title: Determine whether modifier key was pressed
body: <p>I know how to obtain which modifier key was pressed in C# but I don't know how I can actually check if any modifier key was pressed. I need to check it in <code>KeyUp</code> event, is it possible any other way than doing something like <code>if(e.KeyCode != Keys.Control &amp;&amp; e.KeyCode != Keys.Alt &amp;&amp; ...)</code> ? Thanks.</p>