[英]How can i use select to string in linq?
我怎么能使用下面的代碼字符串id =(從.....)如何?
using (StockProcedureDataContext stock = new StockProcedureDataContext())
{
id = (from m in stock.StockTools
from ss in stock.RefStockStatus
where (m.statusid == 3 || m.statusid == 5) &&
ss.id == m.statusid && m.id == ItemID
select m.id);
id = (from m in stock.StockTools
from ss in stock.RefStockStatus
where (m.statusid == 3 || m.statusid == 5) &&
ss.id == m.statusid && m.id == ItemID
select m).ToList()[0].id;
query.Single()
而已。
id = (from m in stock.StockTools
from ss in stock.RefStockStatus
where (m.statusid == 3 || m.statusid == 5) &&
ss.id == m.statusid && m.id == ItemID
select m.id).FirstOrDefault();
如果要檢索單個結果用戶FirstOrDefault()或First() 。
如果使用First()
且結果為null,它將引發異常,但不會引發FirstOrDefault()
。
var query = (from m in stock.StockTools
from ss in stock.RefStockStatus
where (m.statusid == 3 || m.statusid == 5) &&
ss.id == m.statusid && m.id == ItemID
select m.id).FirstOrDefault();
只是為了多樣性...
query.Take(1)
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