I’m binding to an ObjectProxy field and it only works if the proxy already contains the field at the moment the binding is created.

I’m using Flight 1.0 RC.

propertyCache[metadata][value] = propertyCache[value].(child(“metadata”).(@name == metadata).length() > 0);

but this one does:

propertyCache[metadata][value] = propertyCache[value].(child(“metadata”).(@name == “Bindable”).length() > 0);

this is from source code: flight.utils.Type

Someone knows why is this?

“so it looks like just adding that conditional statement to check for the event listener is kind of expensive. But it’s only a 2x performance hit instead of ~7-8x for dispatching an unnecessary event…”

Most events go unlistened to, considering all the property changes and other events on all DisplayObjects and EventDispatcher’s in the system. This check saves significantly in overall performance of any system, while its minimal cost goes unnoticed.

http://forums.adobe.com/message/2204490#2204490

Cheers,
Lance

Recently I’ve been interested in revisiting the binding solution with a completely new method of updating bindings outside of the event flow. This means that any object could be bindable, not just IEventDispatchers, and it would also mean further speed improvements. The only downside to a new solution like this is that it wouldn’t be compatible with Flex at all, where the current binding is seamless.

Overall I think tweening performance issues stem from the Flex invalidation cycle. Binding in Flex isn’t slow enough to be noticeable unless you’re doing many thousands of property changes in the same thread. Of course that is only taking the binding system into account, not any of the Flex code that responds to some of these property changes.

For example, if you tween “alpha”, “x”, and “y” of a 500×500 Panel for 1 second, that can dispatch 50+ events, plus make a billion invalidation calls. If you do “setActualSize” for resizing (which they recommend), that’s another 3 events, so you can have in a single tween: ‘alphaChanged’, ‘xChanged’, ‘yChanged’, ‘widthChanged’, ‘heightChanged’, ‘resize’… every frame! On most computers other than the newest newest, or the ones we soup up, they chop through 2-4 frames of the animation. Terrible. I think it’s from all the binding going on which you don’t need.

Question is, is Flight ready to handle that problem? It seems like it just about is, if you could put in there a “suspendBinding” method that we could set when running our effects and tweens, that would suspend binding events temporarily. That way I can run animations with zero binding events (when I don’t want them, which is almost always), and zero invalidation calls (some of the time).

Any thoughts?
Lance