显示/隐藏ComboBox控件的滚动条提示.

ComboBox控件的dropdown 属性中的showScrollTips属性.

示例：

代码：

<?xml version="1.0" encoding="utf-8"?>

<!-- http://blog.flexexamples.com/2008/07/01/displaying-scroll-tips-on-a-combobox-control-in-flex/ -->

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"

layout="vertical"

verticalAlign="top"

backgroundColor="white">

<mx:Script>

<![CDATA[

private function init():void {

checkBox.selected = comboBox.dropdown.showScrollTips;

}

private function checkBox_change(evt:Event):void {

comboBox.dropdown.showScrollTips = checkBox.selected;

}

]]>

</mx:Script>

<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:ApplicationControlBar dock="true">

<mx:Form styleName="plain">

<mx:FormItem label="showScrollTips:">

<mx:CheckBox id="checkBox"

change="checkBox_change(event);" />

</mx:FormItem>

</mx:Form>

</mx:ApplicationControlBar>

<mx:ComboBox id="comboBox"

dataProvider="{arr}"

creationComplete="init();" />

</mx:Application>

也可以通过AS实现:

<?xml version="1.0" encoding="utf-8"?>

<!-- http://blog.flexexamples.com/2008/07/01/displaying-scroll-tips-on-a-combobox-control-in-flex/ -->

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"

layout="vertical"

verticalAlign="top"

backgroundColor="white"

creationComplete="init();">

<mx:Script>

<![CDATA[

import mx.containers.ApplicationControlBar;

import mx.containers.Form;

import mx.containers.FormItem;

import mx.controls.ComboBox;

import mx.controls.CheckBox;

private var arr:Array;

private var checkBox:CheckBox;

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"});

checkBox = new CheckBox();

checkBox.addEventListener(Event.CHANGE, checkBox_change);

var formItem:FormItem = new FormItem();

formItem.label = "showScrollTips:";

formItem.addChild(checkBox);

var form:Form = new Form();

form.styleName = "plain";

form.addChild(formItem);

var appControlBar:ApplicationControlBar;

appControlBar = new ApplicationControlBar();

appControlBar.dock = true;

appControlBar.addChild(form);

Application.application.addChildAt(appControlBar, 0);

comboBox = new ComboBox();

comboBox.dataProvider = arr;

addChild(comboBox);

callLater(delayedInit);

}

private function delayedInit():void {

checkBox.selected = comboBox.dropdown.showScrollTips;

}

private function checkBox_change(evt:Event):void {

comboBox.dropdown.showScrollTips = checkBox.selected;

}

]]>

</mx:Script>

</mx:Application>