Question

I notice in actionscript 3 that when a handler gets called, its able to access the senders properties. If I dispatch an event from my custom class. can all the listeners inherit all my public properties and methods?

Answer 1

If your handler method is defined in the same class as the dispatching call then you can access the properties, as they are in the scope. This is not generally the case – if you add an event handler to a button’s “click” event for example – then you only have access to the properties of the button through a reference to that button (such as event.target). If you are more familiar with JS or AS2, then I understand why you are confused – in JS and AS2 the properties of an object is rarely in the scope of a method (you always need to use “this” to access instance properties for example).

class Foo extends EventDispatcher {
    public var myProperty: int;
    function thisMethodIsDispatchingEvents() {
        addEventListener("fooEvent", handleFooEvent);
        dispatchEvent(new Event("fooEvent"));
    }
    function handleFooEvent(event: Event) {
        // "myProperty" can be accessed because "handleFooEvent" 
        // is declared in Foo, not because handleFooEvent is an event handler
        trace(myProperty); // Works
    }
}

// in an unrelated class Bar:
class Bar {
    private var _foo: Foo;
    function bar() {
        _foo = new Foo();
        _foo.addEventListener("fooEvent", handleFooEvent);
    }
    function handleFooEvent(event: Event) {
        // "myProperty" can not be accessed directly, only though
        // a reference to a Foo object.
        trace(myProperty); // Fails
        trace(_foo.myProperty); // Works
        trace(event.target.myProperty); // Works
    }
}