怎么在DropdownList下面嵌入图片

　　flex4 的DropdownList下拉框组件本身并不支持下拉框图片，但是可以结合条目渲染器和皮肤使其显示图片。
　　
　　dropdownlist皮肤代码：  flex/spark" xmlns:fb="http://ns.adobe.com/flashbuilder/2009" alpha.disabled=".5" xmlns:mx="library://ns.adobe.com/flex/mx">             In a custom skin class that uses transitions, set the itemDestructionPolicy property to none. -->                                  条目渲染器：  flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx" autoDrawBackground="true" creationComplete="itemrenderer1_creationCompleteHa ndler(event)">    height="30" verticalAlign="middle" >      其使用代码： positionDDL.setStyle("skinClass", DropdownListSkin); positionArray=new ArrayCollection([{label: "最前", source: "../resources/bringtofront.png"}, {label: "前移", source: "../resources/bringforward.png"}, {label: "后移", source: "../resources/sendbackward.png"}, {label: "最后", source: "../resources/sendtoback.png"}]) positionDDL.dataProvider=positionArray; positionDDL.selectedIndex=0;