flex DateField 去掉选择图标

<mx:Style>.NoIconDateField {     skin: ClassReference(null);    /* null the skins defined in default.css */     upSkin: ClassReference(null);     overSkin: ClassReference(null);     downSkin: ClassReference(null);     disabledSkin: ClassReference(null); } </mx:Style><mx:DateField  styleName="NoIconDateField"></mx:DateField>