DataGrid的增加和删除

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
               xmlns:s="library://ns.adobe.com/flex/spark" 
               xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600">
    <s:layout>
        <s:VerticalLayout horizontalAlign="center" verticalAlign="middle"/>
    </s:layout>
    
    <fx:Script>
        <![CDATA[
            import mx.collections.ArrayCollection;
            import mx.collections.Sort;
            import mx.collections.SortField;
            [Bindable]
            private var dgdp:ArrayCollection=new ArrayCollection();
            protected function adddgitem():void
            {
                var o:Object=new Object();
                o.id=in1.text;
                o.name=in2.text;
                o.score=in3.text;
                o.classes=in4.text;
                o.value=in5.text;
                dgdp.addItem(o);
                in1.text="";
                in2.text="";
                in3.text="";
                in4.text="";
                in5.text="";
                
                var sort:Sort=new Sort();
                var sortF:SortField=new SortField("score");//默认按score排序
                sort.fields=new Array(sortF);
                dgdp.sort=sort;
                dgdp.refresh();
                
            }
            
            protected function deldgitem(i:int):void
            {
                if(dg.selectedIndex!=-1){
                    dgdp.removeItemAt(i);
                }else{
                    return ;
                }
            }
            
        ]]>
    </fx:Script>
    
    <fx:Declarations>
        <!-- 将非可视元素（例如服务、值对象）放在此处 -->
    </fx:Declarations>
    <s:DataGrid id="dg" width="400" height="300" requestedRowCount="5" dataProvider="{dgdp}">
        <s:columns>
            <s:ArrayList>
                <s:GridColumn dataField="id" headerText="id"></s:GridColumn>
                <s:GridColumn dataField="name" headerText="name"></s:GridColumn>
                <s:GridColumn dataField="score" headerText="score"></s:GridColumn>
                <s:GridColumn dataField="classes" headerText="classes"></s:GridColumn>
                <s:GridColumn dataField="value" headerText="value"></s:GridColumn>
            </s:ArrayList>
        </s:columns>
    </s:DataGrid>
    <s:HGroup width="400" height="40" verticalAlign="middle" paddingLeft="5">
        <s:TextInput id="in1" width="40"/>
        <s:TextInput id="in2" width="40"/>
        <s:TextInput id="in3" width="40"/>
        <s:TextInput id="in4" width="40"/>
        <s:TextInput id="in5" width="40"/>
        <s:Button label="增加" click="adddgitem()"
                  enabled="{((in1.text=='')||(in2.text=='')||(in3.text=='')||(in4.text=='')||(in5.text==''))?false:true}"/>
        <s:Button label="删除" click="deldgitem(dg.selectedIndex)" enabled="{(dg.selectedIndex!=-1)?true:false}"/>
    </s:HGroup>
</s:Application>