How can I list all the const properties defined in a class

问题

How can i list all the names (and values) of public (and private / protected) const defined in a class ?

public class Layers {

    public const BACKGROUND:String = "background";
    public const PARENT:String = "parent";
    public const MAP:String = "map";
    public const LINES:String = "lines";
    public const POINTS:String = "points";
    public const WINDOWS:String = "windows";

    ... 

    public function isValidValue(type:String) {
        // ...           
        // if type is a value of a constant return TRUE
        // ...
    }

}

回答1:

At runtime, you can use describeType() to list all the public vars (not too sure about consts), and a whole lot more info too.

http://www.adobe.com/livedocs/flash/9.0/ActionScriptLangRefV3/flash/utils/package.html#describeType()

Privates are more tricky to get.

Not sure if it wouldn't be quicker to create an array of the constants and then use array.indexOf(type)

P.S. I also believe there is a JSON version of describeType() now, somewhere.

回答2:

This works with as3 and flex 4.5.1

public static function isValidValue(type:String):Boolean {

        var m_constNameList:XMLList = describeType(Layers).descendants("constant");

        for each(var obj:Object in m_constNameList){
            if (type == Layers[obj.@name]){
                return true;
            }
        }
        return false;
    }