flex中event.preventDefault()方法取消事件的默认行为

mx:DataGrid id= "songList" dataProvider= "{songDB}" width= "100%" height= "100%" editable= "true"
itemEditEnd="itemEditEndHandler(event)" itemEditBeginning= "itemEditBeginningHandler(event)"
>

private function itemEditBeginningHandler(event:DataGridEvent): void
{
if (event.columnIndex== 0 || event.columnIndex== 3 ){
event.preventDefault();
}
}