Binding in flex 3 magic in curly brackets
A lot of things have been said about binding (read basics). But to really understad what is going on behind the scenes lets do some experiments… First to mention is, the curly brackets magic does not work as BindingUtils does. BindingUtils lets you bind only one setter, but curly brackets lets you bind whole logic.
- test1 – notice constant C1 in (binding constants is valid, and is working without Binding meta tag) and some plus inside expression “Working: {C1 + ‘ ‘ + v2}”
- test2 – you can use more curly brackets expressions within one attribute “Working: {C1} {v2.toUpperCase()}”
- test3 – even if you expect function result from your bindable variable it will work “Working: {C1} {uberFunc(v2)}”
- test4 – notice some math functions here “Working: {v3 + v3}, {Math.pow(v3, 2)}”
- test5 – simple Object and Array is not working (nor ArrayCollection using brackets) “Not working: {v4.v}, {v5[0]}, {v6[0]}”
- test6 – getItemAt() on ArrayCollection works just smooth “Working: {v6.getItemAt(0)}”
- test7 – once you use curly brackets you can not remove binding, but binding can be unbinded when binded by BindingUtils. (both getter and setter in bindProperty must be public!)
- test8 – binding works when correct event is dispatched “{foo.gimmeSometing()}”
- test9 – binding with ternary operator is super powerful “{v2 == ‘world’ ? ‘is world’ : ‘not world’}”