public FormItemEdit(OrderItem orderItem) : this()
{
this.OrderItem = orderItem;
this.ItemBindingSource.DataSource = orderItem;
List <Goods> goods = GoodsService.GetAll();
if (goods.Count == 0)
{
GoodsService.Add(new Goods("apple", 100.0));
GoodsService.Add(new Goods("egg", 200.0));
goods = GoodsService.GetAll();
}
goodsBindingSource.DataSource = goods;
}