I read the links provided by Doug (thanks!) and came up with this. Keep
in mind that the "age" property doesn't have an instance field, so
there's no possibility of a corresponding setter. Therefore, the change
event needed to be broadcast from the set dob (i.e., changing one's DOB
also change's one's age). Note that there's a [Bindable] on the whole
class, to allow bindings to other properties.
public function set dob(dob:Date):void {
var oldAge:int = age;
this._dob = dob;
this.dispatchEvent(PropertyChangeEvent.createUpdateEvent(this, "age",
oldAge, age));
}
[Bindable(event="propertyChange")]
public function get age():int{
// Yes, this is a poor algorythm. It's just to illustrate a point!
return (new Date().getTime() - dob.getTime()) / 1000 / 60 / 60 / 24 /
365;
}
--- In [email protected], "Doug McCune" <[EMAIL PROTECTED]> wrote:
>
> You can make read-only properties bindable. In your case your age
property
> is a read-only property since it only has a getter. The normal
bindable
> stuff doesn't work on that because bindable properties require both a
getter
> and a setter to work. But if you define only a getter you can still
use the
> [Bindable] metadata tag, but you have to dispatch a custom event that
tells
> everything that the value has updated.
>
> Check out these links:
> http://www.rubenswieringa.com/blog/binding-read-only-accessors-in-flex
>
http://dynamicflash.com/2006/12/databinding-to-read-only-properties-in-f\
lex-2/
>
