Passing Cevent Param To Event Handler

I just want to pass an event handler to onAfterValidate method of my model but how should I pass parameter to the event handler. I initialized the event handler like this:

$model->onAfterValidate = array(new AnEventClass, 'eventHandler');

How should I pass this CEvent to that handler?

new CEvent($model, array('my_param' => $param_value));


don’t really know. the only $event passing that I know of is in the behaviors