c#-如何解决“不能多次枚举查询结果”？

如果我尝试编写以下代码：错误返回给我：查询结果不能多​​次枚举

  public void StartTransaction()
        {
            using (var stockMovementCtx = new StockMovementCtxDataContext())
            using (var scope = new TransactionScope())
            {

                var stockMovementItems = from s in stockMovementCtx.spStockMovementForTransaction(TicketID, ItemTypeNo, ItemID, TransactionType,
                                                                                                  FromLocation, ToLocation, Qty, PersonelNo, cuser
                                                                                                  )
                                         select s;

                ReturnCode = stockMovementItems.First().ReturnCode;
               // MessageBox.Show(stockMovementItems.First().ToString());
                ReturnMsg = stockMovementItems.First().ReturnMessage;
                TransactionType = stockMovementItems.First().TransactionType;
                TicketID = stockMovementItems.First().TicketID;

alt text http://i45.tinypic.com/avistc.png

细节：
alt text http://i48.tinypic.com/wss2va.png

详细说明：

alt text http://i48.tinypic.com/waonbq.png

解决方法:

简短修正：

var FirstChild = stockMovementItems.First();

然后

ReturnCode = FirstChild.ReturnCode;
//etc...

要么

(from s in stockMovementCtx.spStockMovementForTransaction(TicketID, ItemTypeNo, ItemID, TransactionType, FromLocation, ToLocation, Qty, PersonelNo, cuser) select s).ToList();

但是后者是对Linq的一种滥用.

更长的答案是,无论stockMovementCtx.spStockMovementForTransaction(..)是什么,它都仅支持正向读取.因此,当您调用First()时,您将前进到下一个结果,并且无法返回.

标签：visual-studio-2008,linq-to-sql,linq,c,visual-studio
来源： https://codeday.me/bug/20191106/1999218.html