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" />
                <quote date="8/9/2007" open="39.9" close="40.75" />
                <quote date="8/8/2007" open="39.61" close="40.23" />
                <quote date="8/7/2007" open="39.08" close="39.42" />
                <quote date="8/6/2007" open="38.71" close="39.38" />
                <quote date="8/3/2007" open="39.47" close="38.75" />
                <quote date="8/2/2007" open="39.4" close="39.52" />
                <quote date="8/1/2007" open="40.29" close="39.58" />
            </mx:XMLList>
        </mx:source>
    </mx:XMLListCollection>

    <mx:Array id="seriesFilterArr" />

    <mx:ApplicationControlBar dock="true">
        <mx:CheckBox id="checkBox"
                label="toggle series filters:"
                labelPlacement="left"
                selected="false"
                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>