我找不到这个具体的例子,所以我发布了这个问题.任何帮助赞赏.
我有两个大的通用列表,都有超过300K的项目.
我循环遍历第一个列表以回读信息并为动态生成新列表的新项目,但是我需要在第二个列表中搜索并根据三个匹配条件返回一个值,如果发现要添加到列表,但是你可以想象,这样做300k * 300k次需要时间.
有什么方法可以更有效地做到这一点吗？
我的代码：
var reportList = new List<StocksHeldInCustody>();
foreach (var correctDepotHolding in correctDepotHoldings)
{
var reportLine = new StocksHeldInCustody();
reportLine.ClientNo = correctDepotHolding.ClientNo;
reportLine.Value = correctDepotHolding.ValueOfStock;
reportLine.Depot = correctDepotHolding.Depot;
reportLine.SEDOL = correctDepotHolding.StockCode;
reportLine.Units = correctDepotHolding.QuantityHeld;
reportLine.Custodian = "Unknown";
reportLine.StockName = correctDepotHolding.StockR1.Trim() + " " + correctDepotHolding.StockR2.Trim();
//Get custodian info
foreach (var ccHolding in ccHoldList)
{
if (correctDepotHolding.ClientNo != ccHolding.ClientNo) continue;
if (correctDepotHolding.Depot != ccHolding.Depot) continue;
if (correctDepotHolding.StockCode != ccHolding.StockCode) continue;
if (correctDepotHolding.QuantityHeld != ccHolding.QuantityHeld) continue;
reportLine.Custodian = ccHolding.Custodian;
break;
}
reportList.Add(reportLine);
}
解决方法
正如Pranay所说,加入可能是你想要的：
var query = from correct in correctDepotHoldings
join ccHolding in ccHoldList
on new { correct.ClientNo,correct.Depot,correct.StockCode,correct.QuantityHeld }
equals new { ccHolding.ClientNo,ccHolding.Depot,ccHolding.StockCode,ccHolding.QuantityHeld }
// TODO: Fill in the properties here based on correct and ccHolding
select new StocksHeldInCustody { ... };
var reportList = query.ToList();
