gtk-sharp 0.0.0.0 Gtk# is thread aware, but not thread safe; See the Gtk# Thread Programming for details. Event handler. The event utilizes this delegate: Event data is passed via the parameter. To attach a 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. System.Delegate System.ICloneable System.Runtime.Serialization.ISerializable System.Void