c# - 避免额外的循环并且找不到源类型 int 的查询模式的实现 Select not found

Question

如何在 LINQ 任务本身中避免额外循环和构造顺序。

GetOrderListDataContext orderListDaCtx = new GetOrderListDataContext(address);
// This line showing compiler error could not find implementation of query pattern for source type int Select not found
var orderList = from order in orderListDaCtx.Base_Purchase_GetOrderListByUser_WS(request.UserGuid, request.CountryCode, request.FromDate, request.ToDate)
                select order;
// Here how i can avoid this loop and construct order object in the LINQ itself above                   
List<Order> orders = new List<Order>();
foreach (var order in orderList)
{
    orders.Add(new Order
     {
         OrderKey = order.OrderKey,
         UserEmail = order.UserEmail,
         CreatedDate = order.CreatedDate
     });
}
return orders;

Answer 1

你是这个意思吗？

GetOrderListDataContext orderListDaCtx = new GetOrderListDataContext(address);
var orderList = from order in orderListDaCtx.Base_Purchase_GetOrderListByUser_WS(request.UserGuid, request.CountryCode, request.FromDate, request.ToDate)
select new Order{
         OrderKey = order.OrderKey,
         UserEmail = order.UserEmail,
         CreatedDate = order.CreatedDate
}

return orderList.ToList();