Flex 支持CTRLZ的TextArea

public class UndoTextArea extends TextArea
    {
        
        private var _undoManager:UndoManager;
        
        public function UndoTextArea()
        {
            super();
            
            _undoManager=new UndoManager();
            
            this.addEventListener(KeyboardEvent.KEY_UP,undoKeyUpHandler);
            this.addEventListener(FlexEvent.CREATION_COMPLETE,creationCompleteHandler);
        }
        
        private function creationCompleteHandler(evt:FlexEvent):void 
        { 
            
            this.textFlow.interactionManager=new EditManager(this._undoManager);
            
        }
        
        private function undoKeyUpHandler(evt:KeyboardEvent):void 
        { 
            
            if (evt.ctrlKey&&evt.keyCode == 90) 
            { 
                _undoManager.undo();
                
            } 
            
        } 
    }

这里使用了KEY_UP事件，其实更合理的是用KEY_DOWN，只是在IE下CTRL-Z被浏览器截获了，我们的程序捕获不到！