Flex中如何利用seriesFilters属性，添加/删除LineChart图表曲线阴影

<?xml version="1.0"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
layout="vertical"
verticalAlign="middle"
backgroundColor="white" viewSourceURL="srcview/index.html">

<mx:Script>
<!--[CDATA[
private function init(evt:Event):void {
var chart:LineChart = evt.currentTarget as LineChart;
seriesFilterArr = chart.seriesFilters;
}

private function checkBox_click(evt:MouseEvent):void {
var len:uint = lineChart.seriesFilters.length;
if (len > 0) {
lineChart.seriesFilters = [];
} else {
lineChart.seriesFilters = seriesFilterArr;
}
}
]]-->
</mx:Script>

<mx:XMLListCollection id="dp">
<mx:source>
<mx:XMLList>
<quote date="8/27/2007" open="40.38" close="40.81" />
<quote date="8/24/2007" open="40.5" close="40.41" />
<quote date="8/23/2007" open="40.82" close="40.6" />
<quote date="8/22/2007" open="40.4" close="40.77" />
<quote date="8/21/2007" open="40.41" close="40.13" />
<quote date="8/20/2007" open="40.55" close="40.74" />
<quote date="8/17/2007" open="40.18" close="40.32" />
<quote date="8/16/2007" open="39.83" close="39.96" />
<quote date="8/15/2007" open="40.22" close="40.18" />
<quote date="8/14/2007" open="41.01" close="40.41" />
<quote date="8/13/2007" open="41" close="40.83" />
<quote date="8/10/2007" open="41.3" close="41.06" />
</mx:XMLList>
</mx:source>
</mx:XMLListCollection>

<mx:Array id="seriesFilterArr" />

<mx:ApplicationControlBar dock="true">
<mx:CheckBox id="checkBox"
label="toggle series filters:"
labelPlacement="left"
click="checkBox_click(event);" />
</mx:ApplicationControlBar>

<mx:LineChart id="lineChart"
showDataTips="true"
dataProvider="{dp}"
width="100%"
height="100%"
creationComplete="init(event);">

<!-- vertical axis -->
<mx:verticalAxis>
<mx:LinearAxis baseAtZero="false" title="Price" />
</mx:verticalAxis>

<!-- horizontal axis -->
<mx:horizontalAxis>
<mx:CategoryAxis id="ca" categoryField="@date" title="Date" />
</mx:horizontalAxis>

<!-- horizontal axis renderer -->
<mx:horizontalAxisRenderers>
<mx:AxisRenderer axis="{ca}" canDropLabels="true" />
</mx:horizontalAxisRenderers>

<!-- series -->
<mx:series>
<mx:LineSeries yField="@close" form="curve" displayName="Close" />
<mx:LineSeries yField="@open" form="curve" displayName="Open" />
</mx:series>

</mx:LineChart>

</mx:Application>