Flex AdvancedDatagrid的bug

Flex AdvancedDataGrid有一个bug，当浏览器最大化时，datagrid处于可编辑状态，并且datagrid中有多条数据，最好在有滚动条出现，当你编辑靠下面的数据时（光标停留在编辑框内），这时候双击浏览器，还原。会出现前台bug（有安装flash debug版本的可以看到Alert）。
错误代码如下：

TypeError: Error #1010: A term is undefined and has no properties.
	at mx.controls::AdvancedDataGridBaseEx/makeRowsAndColumns()[E:\dev\4.x\frameworks\projects\datavisualization\src\mx\controls\AdvancedDataGridBaseEx.as:2220]
	at mx.controls::AdvancedDataGrid/makeRowsAndColumns()[E:\dev\4.x\frameworks\projects\datavisualization\src\mx\controls\AdvancedDataGrid.as:1999]
	at mx.controls.listClasses::AdvancedListBase/makeRowsAndColumnsWithExtraRows()[E:\dev\4.x\frameworks\projects\datavisualization\src\mx\controls\listClasses\AdvancedListBase.as:4002]
	at mx.controls.listClasses::AdvancedListBase/updateDisplayList()[E:\dev\4.x\frameworks\projects\datavisualization\src\mx\controls\listClasses\AdvancedListBase.as:3574]
	at mx.controls::AdvancedDataGridBaseEx/updateDisplayList()[E:\dev\4.x\frameworks\projects\datavisualization\src\mx\controls\AdvancedDataGridBaseEx.as:2016]
	at mx.controls::AdvancedDataGrid/updateDisplayList()[E:\dev\4.x\frameworks\projects\datavisualization\src\mx\controls\AdvancedDataGrid.as:2899]
	at com.sft.gec.component.common::BaseAdvancedDataGrid/updateDisplayList()[C:\ccsnapshort_views\e515896_DEV_gec_was_04.00_pchz_tc\ssgm03\gec_was\src\gec\WebContent\WEB-INF\flex\user_classes\com\sft\gec\component\common\BaseAdvancedDataGrid.as:93]
	at mx.controls.listClasses::AdvancedListBase/validateDisplayList()[E:\dev\4.x\frameworks\projects\datavisualization\src\mx\controls\listClasses\AdvancedListBase.as:3472]
	at mx.managers::LayoutManager/validateDisplayList()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:663]
	at mx.managers::LayoutManager/doPhasedInstantiation()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:736]
	at mx.managers::LayoutManager/validateNow()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:795]
	at mx.core::Application/resizeHandler()[E:\dev\4.x\frameworks\projects\framework\src\mx\core\Application.as:1683]
	at mx.core::Application/commitProperties()[E:\dev\4.x\frameworks\projects\framework\src\mx\core\Application.as:1073]
	at mx.core::UIComponent/validateProperties()[E:\dev\4.x\frameworks\projects\framework\src\mx\core\UIComponent.as:7933]
	at mx.managers::LayoutManager/validateProperties()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:572]
	at mx.managers::LayoutManager/doPhasedInstantiation()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:730]
	at mx.managers::LayoutManager/validateNow()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:795]
	at mx.core::Application/resizeHandler()[E:\dev\4.x\frameworks\projects\framework\src\mx\core\Application.as:1683]
	at flash.events::EventDispatcher/dispatchEventFunction()
	at flash.events::EventDispatcher/dispatchEvent()
	at mx.managers::SystemManager/Stage_resizeHandler()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\SystemManager.as:2971]

这个原因是因为在调用updateDisplayList时，itemEditorInstance和editedItemPosition不为空引起的。
解决方法：

	import flash.events.Event;
	import mx.events.AdvancedDataGridEventReason;
	import mx.events.AdvancedDataGridEvent;

	public class BaseAdvancedDataGrid extends AdvancedDataGrid {
		
		private var resizeHandling:Boolean = false;
		
		public function BaseAdvancedDataGrid()
		{
						/**
			 * UI function break when editing a item(cusor focus in) and dobule click IE browser 
			 */
			addEventListener(Event.RESIZE, changeWindowSizeHandler, false, 0, true);
		}
		
		/**
		 * UI function break when editing a item(cusor focus in) and dobule click IE browser 
		 */
		override protected function updateDisplayList(unscaledWidth:Number,unscaledHeight:Number):void{
			if(super.itemEditorInstance!=null&&resizeHandling==true){
	    		super.itemEditorInstance = null;
	    		super.editedItemPosition = null;
	    	}
			super.updateDisplayList(unscaledWidth,unscaledHeight);
		}
		private function changeWindowSizeHandler(event:Event):void {
			
			if(super.itemEditorInstance!=null){
				resizeHandling = true;
				super.endEdit(AdvancedDataGridEventReason.OTHER);
				resizeHandling = false;
			}
		}
}

该类继承AdvancedDataGrid 并监听RESIZE事件，当resize事件触发时，判断当datagrid正在被编辑，那么就结束编辑。之所以重写updateDisplayList这个方法，是因为，有些editor item并不是简单的text input，而是复杂的组件，比如多选下拉框，当这个被编辑并还原窗口时，会在endEdit方法中会调用remove child方法，而这个方法同样会调用updateDisplayList，所以还是会报相应的错误，所以针对这种情况，直接将super.itemEditorInstance 和super.editedItemPosition 置为空。