请教checkbox的label文字怎么换行

package
{
    import flash.text.TextLineMetrics;
    
    import mx.controls.CheckBox;

    public class MyCheckBox extends CheckBox
    {
        public function MyCheckBox()
        {
            super();
        }
        
        override protected function createChildren():void
        {
            super.createChildren();
            
            if (textField != null) {
                textField.multiline = true;
                textField.wordWrap = true;
            }
        }
        
        override protected function updateDisplayList(unscaledWidth:Number,
                                                  unscaledHeight:Number):void {
            super.updateDisplayList(unscaledWidth,unscaledHeight);

            var lineMetrics:TextLineMetrics = measureText(label);
            var textWidth:Number = lineMetrics.width + 6;
            var textHeight:Number = lineMetrics.height + 4;
            var paddingLeft:Number = textField.getStyle("paddingLeft") as Number;
            var paddingRight:Number = textField.getStyle("paddingRight") as Number;
            var paddingTop:Number = textField.getStyle("paddingTop") as Number;
            var paddingBottom:Number = textField.getStyle("paddingBottom") as Number;
            
            
            textHeight = (textWidth/(textField.width - paddingLeft - paddingRight))*(textHeight + paddingTop+paddingBottom);
            textField.height = textHeight;
        }
        
    }
}