class DatagridEvents extends EventGroup {
  var change:Event<String->DataGrid->Void>;
}
class Datagrid { 
  var events : DatagridEvents;
}

typedef ListenerHandlers = {
  var onDataChange : Binding;
}

class Listener implements EventHandlers<ListenerHandlers>
{
  var handlers : ListenerHandlers;

  function onDataChange(value:String, grid:Datagrid){ ... } 
  public function new(){ 
    var d = new Datagrid(); 
    handlers = {
      onDataChange : d.events.change.bind(onDataChange);
    }

    handlers.onDataChange.disable(); // Temp. disable this handler (it will not listen to events)
    Event.unbind(this); // Unsubscribes all handlers for this object
  }
}