protected function applicationCompleteHandler(event:FlexEvent):void
{
    var array:Array = [];
    array.push(new Vga("a",10));
    array.push(new Vga("c",2));
    array.push(new Vga("f",1.3));
    array.push(new Vga("d",1.1));
    array.push(new Vga("e",16));
    array.push(new Vga("b",0));
    trace(array.toString());
    //output:   [a,10],[c,2],[f,1.3],[d,1.1],[e,16],[b,0]
    var defaultSort:Array = array.sort();//默认排序
    trace(defaultSort.toString());
    //output:   [a,10],[b,0],[c,2],[d,1.1],[e,16],[f,1.3]
    var sortFunArray:Array = array.sort(sortFun);//使用自定义方法排序
    trace(sortFunArray.toString());
    //output:   [b,0],[d,1.1],[f,1.3],[c,2],[a,10],[e,16]
}

/**自定义排序方法*/            
public function sortFun(a:Vga,b:Vga):int{
    if(a.price < b.price){
    return -1; //a在前,b在后
    }else if(a.price == b.price){
    return 0; //ab位置不变
    }else{
    return 1; //b在前,a在后
    }
}



/**排序VO对象*/
public class Vga
{
    public var name:String;
    public var price:Number;
    
    public function Vga(name:String,price:Number)
    {
    this.name = name;
    this.price = price;
    }
        
    public function toString():String{
    return "["+this.name+","+this.price+"]";
    }
}

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
    <mx:Script>
        <![CDATA[
            import mx.collections.SortField;
            import mx.collections.Sort;
            import mx.collections.ArrayCollection;
            private var acSort:ArrayCollection=
            new ArrayCollection([{id:0,userName:"zhangSan",age:21},
                                {id:2,userName:"liSi",age:24},
                                {id:1,userName:"wangWu",age:31}]);
            
            
            private function sortAc():ArrayCollection{
                var sort:Sort=new Sort();
                //按照ID升序排序
                sort.fields=[new SortField("id")];
                
                //按照userName降序排序
                sort.fields=[new SortField("userName",true,true)];
                
                //先按ID升序,再按userName降序
                sort.fields[new SortField("id"),new SortField("userName",true,true)];
                acSort.sort=sort;
                acSort.refresh();//更新
                return acSort;
            }
            
            /*
            其实看看API就一目了然
            SortField () 构造函数 

            public function SortField(name:String = null, 
                        caseInsensitive:Boolean = false, 
                        descending:Boolean = false, 
                        numeric:Object = null)
                                    
            参数  
            name:String (default = null) — 此字段用来进行比较的属性的名称。如果该对象为简单类型，则传递 null。 
            caseInsensitive:Boolean (default = false) — 在对字符串进行排序时，指示比较运算符是否忽略值的大小写。
            descending:Boolean (default = false) — 指示比较运算符是否按降序排列项目。  
                 
            numeric:Object (default = null) — 指示比较运算符是否按编号而不按字母顺序比较排序项目。 
            */            
        ]]>
    </mx:Script>
</mx:Application>