How do I change the value of an item in a Flex ArrayCollection

I have an ArrayCollection with values predefined. I want to assign a new value to items in the arrayCollection but can not figure out how. Basically I want to do something like this: acGuages.itemUpdated(0).thevalue = 90; (Changing the value fro开发者_如何学编程m 25 to 90). Thanks.

    private var arrayGuages:Array=[
        {thevalue:"25",height:"115"},
        {thevalue:"45",height:"115"},
        {thevalue:"15",height:"115"},
        {thevalue:"95",height:"115"},
        ];

    [Bindable] 
    public var acGuages:ArrayCollection=new ArrayCollection(arrayGuages);

    acGuages.itemUpdated(0).thevalue = 90;

ArrayCollection supports random access to its elements, just like Array. In other words, your line:

acGuages.itemUpdated(0).thevalue = 90;

Can be rewritten as:

acGuages[0].thevalue = 90;

And it should all work as expected.