Setting the horizontal scroll policy on a Spark DropDownList control in Flex 4

The following example shows how you can set the horizontal scroll policy on a Spark DropDownList control in Flex 4 by setting the horizontalScrollPolicy style on the drop down menu’s Scroller skin part.

The following example(s) require Flash Player 10 and the Adobe Flex 4 SDK. To download the Adobe Flash Builder 4 trial, see www.adobe.com/products/flex/. To download the latest nightly build of the Flex 4 SDK, see opensource.adobe.com/wiki/display/flexsdk/Download+Flex+4.

For more information on getting started with Flex 4 and Flash Builder 4, see the official Adobe Flex Team blog.

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2010/02/06/setting-the-horizontal-scroll-policy-on-a-spark-dropdownlist-control-in-flex-4/ -->
<s:Application name="Spark_DropDownList_scroller_horizontalScrollPolicy_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009" 
        xmlns:s="library://ns.adobe.com/flex/spark" 
        xmlns:mx="library://ns.adobe.com/flex/mx">
 
    <fx:Script>
        <![CDATA[
            import mx.core.ScrollPolicy;
        ]]>
    </fx:Script>
 
    <s:DropDownList id="ddl"
            width="100"
            horizontalCenter="0" top="20"
            open="ddl.scroller.setStyle('horizontalScrollPolicy', ScrollPolicy.OFF);">
        <s:dataProvider>
            <s:ArrayList source="[Accordion,ApplicationControlBar,Alert,Box,Button,ButtonBar,Canvas,ColorPicker]" />
        </s:dataProvider>
    </s:DropDownList>
 
</s:Application>

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View source is enabled in the following example.

Or you can set the horizontalScrollPolicy style in an external .CSS file or <Style/> block, as seen in the following example:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2010/02/06/setting-the-horizontal-scroll-policy-on-a-spark-dropdownlist-control-in-flex-4/ -->
<s:Application name="Spark_DropDownList_scroller_horizontalScrollPolicy_test"
        xmlns:fx="http://ns.adobe.com/mxml/2009" 
        xmlns:s="library://ns.adobe.com/flex/spark" 
        xmlns:mx="library://ns.adobe.com/flex/mx">
 
    <fx:Style>
        @namespace s "library://ns.adobe.com/flex/spark";
 
        s|Group#dropDown #scroller {
            horizontalScrollPolicy: off;
        }
    </fx:Style>
 
    <s:DropDownList id="ddl"
            width="100"
            horizontalCenter="0" top="20">
        <s:dataProvider>
            <s:ArrayList source="[Accordion,ApplicationControlBar,Alert,Box,Button,ButtonBar,Canvas,ColorPicker]" />
        </s:dataProvider>
    </s:DropDownList>
 
</s:Application>

This entry is based on a beta version of the Flex 4 SDK and therefore is very likely to change as development of the Flex SDK continues. The API can (and will) change causing examples to possibly not compile in newer versions of the Flex 4 SDK.

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