设置ComboBox控件的下拉栏的宽度.

ComboBox控件的dropdownWidth属性.
示例：

代码：

<? xml version="1.0" encoding="utf-8" ?>
<!--  http://blog.flexexamples.com/2008/07/02/setting-the-width-of-the-dropdown-menu-on-a-combobox-control-in-flex/  -->
< mx:Application  xmlns:mx ="http://www.adobe.com/2006/mxml"
        layout ="vertical"
        verticalAlign ="top"
        backgroundColor ="white" >

     < mx:Array  id ="arr" >
         < mx:Object  label ="One"   />
         < mx:Object  label ="Two"   />
         < mx:Object  label ="Three"   />
         < mx:Object  label ="Four"   />
         < mx:Object  label ="Five"   />
         < mx:Object  label ="Six"   />
         < mx:Object  label ="Seven"   />
         < mx:Object  label ="Eight"   />
         < mx:Object  label ="Nine"   />
         < mx:Object  label ="Ten"   />
     </ mx:Array >

     < mx:ComboBox  id ="comboBox"
            dataProvider =" {arr} "
            dropdownWidth ="200"   />

</ mx:Application >

也可以通过AS来实现.

<? xml version="1.0" encoding="utf-8" ?>
<!--  http://blog.flexexamples.com/2008/07/02/setting-the-width-of-the-dropdown-menu-on-a-combobox-control-in-flex/  -->
< mx:Application  xmlns:mx ="http://www.adobe.com/2006/mxml"
        layout ="vertical"
        verticalAlign ="top"
        backgroundColor ="white"
        initialize ="init();" >

     < mx:Script >
         <![CDATA[
            import mx.controls.ComboBox;

            private var arr:Array;
            private var comboBox:ComboBox;

            private function init():void {
                arr = [];
                arr.push({label:"One"});
                arr.push({label:"Two"});
                arr.push({label:"Three"});
                arr.push({label:"Four"});
                arr.push({label:"Five"});
                arr.push({label:"Six"});
                arr.push({label:"Seven"});
                arr.push({label:"Eight"});
                arr.push({label:"Nine"});
                arr.push({label:"Ten"});

                comboBox = new ComboBox();
                comboBox.dataProvider = arr;
                comboBox.dropdownWidth = 200;
                addChild(comboBox);
            }
         ]]>
     </ mx:Script >

</ mx:Application >