<ThreadSafetyStatement>Gtk# is thread aware, but not thread safe; See the <linklocation="node:gtk-sharp/programming/threads">Gtk# Thread Programming</link> for details.</ThreadSafetyStatement>
<para>The <seecref="M:Gtk.Widget.StateChanged"/> event utilizes this delegate:</para>
<para>Event data is passed via the <seecref="T:Gtk.StateChangedArgs"/> parameter.</para>
<para>To attach a <seecref="T:Gtk.StateChangedHandler"/> to an event, add the StateChangedHandler instance to the event. The methods referenced by the StateChangedHandler instance are invoked whenever the event is raised, until the StateChangedHandler is removed from the event.</para>