GroupCollection2比较函数拆分组

Question

在下面的代码中GroupCollection2比较函数将一个组拆分为2个组。当我删除比较函数时，它工作正常，但当添加比较排序列时，它将一个组拆分为不同的。

  <?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" >


<fx:Declarations>
    <!-- Place non-visual elements (e.g., services, value objects) here -->
    <fx:XMLList id="defaultColumns">
        <ROW>
            <NAME>A</NAME>
            <COLUMN_SRT_ORDR>4</COLUMN_SRT_ORDR>
            <GROUP_DESCRIPTION>1. Description</GROUP_DESCRIPTION>
        </ROW>
        <ROW>
            <NAME>B</NAME>
            <COLUMN_SRT_ORDR>11</COLUMN_SRT_ORDR>
            <GROUP_DESCRIPTION>1. Description</GROUP_DESCRIPTION>
        </ROW>
        <ROW>
            <NAME>C</NAME>
            <COLUMN_SRT_ORDR>36</COLUMN_SRT_ORDR>
            <GROUP_DESCRIPTION>1. Description</GROUP_DESCRIPTION>
        </ROW>
        <ROW>
            <NAME>D</NAME>
            <COLUMN_SRT_ORDR>41</COLUMN_SRT_ORDR>
            <GROUP_DESCRIPTION>1. Description</GROUP_DESCRIPTION>
            <OPTIONS/>
        </ROW>
        <ROW>
            <NAME>E</NAME>
            <COLUMN_SRT_ORDR>2</COLUMN_SRT_ORDR>
            <GROUP_DESCRIPTION>2.Budget</GROUP_DESCRIPTION>
        </ROW>
        <ROW>
            <NAME>F</NAME>
            <COLUMN_SRT_ORDR>6</COLUMN_SRT_ORDR>
            <GROUP_DESCRIPTION>2.Budget</GROUP_DESCRIPTION>
        </ROW>
        <ROW>
            <NAME>G</NAME>
            <COLUMN_SRT_ORDR>7</COLUMN_SRT_ORDR>
            <GROUP_DESCRIPTION>2.Budget</GROUP_DESCRIPTION>
        </ROW>
        <ROW>
            <NAME>G</NAME>
            <GROUP_DESCRIPTION>DEBUG</GROUP_DESCRIPTION>
            <COLUMN_SRT_ORDR>10003</COLUMN_SRT_ORDR>
            <OPTIONS/>
        </ROW>

        <ROW>
            <NAME>H</NAME>
            <GROUP_DESCRIPTION>DEBUG</GROUP_DESCRIPTION>
            <COLUMN_SRT_ORDR>10005</COLUMN_SRT_ORDR>
            <OPTIONS/>
        </ROW>
        <ROW>
            <NAME>I</NAME>
            <COLUMN_CAPTION>Sql</COLUMN_CAPTION>
            <COLUMN_WIDTH>1</COLUMN_WIDTH>
            <GROUP_DESCRIPTION>DEBUG</GROUP_DESCRIPTION>
            <COLUMN_SRT_ORDR>10006</COLUMN_SRT_ORDR>
            <OPTIONS/>
        </ROW>
    </fx:XMLList>
    <mx:GroupingCollection2 id="colGroup" source="{defaultColumns}">
        <mx:grouping>
            <mx:Grouping>
                <mx:GroupingField name="GROUP_DESCRIPTION"  compareFunction="myCompare"/>
            </mx:Grouping>
        </mx:grouping>
    </mx:GroupingCollection2>
</fx:Declarations>
<fx:Script>
    <![CDATA[
        import mx.controls.Alert;
        import mx.events.FlexEvent;
        import mx.events.IndexChangedEvent;
        private function myCompare(a:Object, b:Object):int{

            var result:int=-1;
            if(parseInt(a.COLUMN_SRT_ORDR)<parseInt(b.COLUMN_SRT_ORDR))
                result=-1;
            else if(parseInt(a.COLUMN_SRT_ORDR)==parseInt(b.COLUMN_SRT_ORDR))
                result=0;
            else
                result=1;
            return result;
        }   

    ]]>
</fx:Script>
<mx:TabNavigator id="groupTabs" borderStyle="solid" width="100%" initialize="{colGroup.refresh()}" >
    <mx:Repeater dataProvider="{colGroup.getRoot()}" id="t">

        <mx:VBox  label="{t.currentItem.GroupLabel}" width="100%" height="100%">

        </mx:VBox>
    </mx:Repeater>

</mx:TabNavigator>  


</s:Application>