[iNils]

Способ 1:

class Test {
	private var _x:Number;
	function Test () {
		
	}
	public function onPres():Void {
		trace (this._x)
	}
}

Способ 2:

class Test {
	function Test () {
		
	}
	
	public function onPres():Void {
		trace (this["_x"])        
	}
}

Способ 3 (самый правильный):

class Test {
	private var __mc:MovieClip;
	function Test (mc:MovieClip) {
		__mc = mc;
	}
	
	public function onPres():Void {
		trace(__mc._x);
	}
}

import mx.utils.Delegate;
var test:Test = new Test(mc);
mc.onPress = Delegate.create (test, test.onPres);