Trying something with addEventListener

I have been reading as3 documentation and the type of listener is supposedly a string value. So instead of creating a button the common way:

button1.addEventListener(MouseEvent.CLICK, clickaction);

I am trying to do it a different way:

var eventtype:String = "MouseEvent.CLICK";
button1.addEventListener(eventtype, clickaction);

I don’t get any errors when doing it this way but the MouseEvent.CLICK event is not added to the button. Any tried this before or have any thoughts?