如何重构此代码以便我可以集中投影？
public IEnumerable<ItemDto> GetItemsByType(int itemId,ItemType itemType)
{
IEnumerable<ItemDto> items = null;
try
{
var tempItems= _Items.Get(i => i.ItemId == itemId
&& o.Active == true);
switch (itemType)
{
case ItemType.Normal:
items = from item in tempItems
select new ItemDto
{
// many fields here
};
break;
case ItemType.Damaged:
items = from item in tempItems
join itemDetail in _ItemDetails.Get() on item.ID equals itemDetail.ItemID
select new ItemDto
{
// many fields here
};
break;
case ItemType.Fixed:
items = from item in tempItems
join itemDetail in _ItemDetails.Get() on item.ID equals itemDetail.ItemID
where item.Status.ToLower() == "fixed"
select new ItemDto
{
// many fields here
};
break;
// more case statements here...
default:
break;
}
}
catch { ... }
}
基本上,我在每个案例陈述中都有很多案例陈述和长期预测.我担心一旦DTO需要改变,比如添加一个新字段,其他情况的投影可能彼此不一致(忘记或错过更新).我该如何集中这个？
解决方法
你能这样接近吗？
var query = tempItems.AsQueryable();
switch(itemType)
{
case ItemType.Damaged:
query.Join(...);
break;
case ItemType.Fixed:
query.Where(...);
}
query.Select(e => new ItemDto{//Lots of properties});
return query.ToList();
