I got the solutions, below is the code check it out....:)
<?xml version="1.0" encoding="utf- 8"?>
<mx:Canvas xmlns:mx="http://www.adobe. com/2006/ mxml" width="400"
height="300" >
<mx:Script>
<![CDATA[
import mx.effects.easing. Bounce;
]]>
</mx:Script>
<mx:ComboBox id="comboBox" openDuration= "700" enabled="false"
mouseOver="comboBox.enabled?comboBox.open():null;"
closeDuration= "100" x="30" y="86" openEasingFunction= "{Bounce.
easeOut}" closeEasingFunction ="{Bounce. easeIn}">
<mx:dataProvider>
<mx:Array>
<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:Array>
</mx:dataProvider>
</mx:ComboBox>
</mx:Canvas>
