c# - 使用 LINQ to SQL 计算运行总计

Question

我有一个 WPF C# 应用程序，它通过 SQL-LINQ 连接访问数据并将其放在数据网格上。我添加了“运行点数”列，并一直在尝试找出如何正确填充此列。我通过搜索网络找到了几种方法，但这些方法都不适合我的特定设置。大多数时候我都会陷入无限循环。我希望运行点数列是累积的，并且计算顺序从最早的“关闭时间”开始。

Close Time   Profit    Running Profit
 10.09.11     $10          $10 
 10.10.11     $20          $30 
 10.11.11     $15          $45 

这里是代码摘要。我希望有人可以建议如何修复此代码，并提供帮助我实现此功能所需的任何相关信息:

public void RefreshClose() {
    if (CloseTradeCollection == null) return;
    var i = 0;

    if (StaticTool.SelectedAccount == null) {
        ExistCloseTrade = false;
        CloseTradeCollection.Clear();
        return;
    }

    Account = StaticTool.SelectedAccount;

    foreach (var trade in GetClosedTradesFromDb()) {
        if (CloseTradeCollection.Count <= i) {
            ExistCloseTrade = true;
            var tradeDetails = new Trade {
                Id = trade.id,
                Ticket = trade.ticket,
                OpenTime = trade.opentime,
                CloseTime = trade.closetime,
                Symbol = trade.symbol,
                OpenPrice = trade.openprice,
                ClosePrice = trade.closeprice,
                Profit = trade.profit,
                Comment = trade.comment.Trim(),
            };

            tradeDetails.History = tradeDetails.CloseTime - tradeDetails.OpenTime;
            CloseTradeCollection.Add(tradeDetails);
        }

        else {
            var tradeDetails = CloseTradeCollection[i];
            tradeDetails.Id = trade.id;
            tradeDetails.Ticket = trade.ticket;
            tradeDetails.OpenTime = trade.opentime;
            tradeDetails.CloseTime = trade.closetime;
            tradeDetails.Symbol = trade.symbol;
            tradeDetails.OpenPrice = trade.openprice;
            tradeDetails.ClosePrice = trade.closeprice;
            tradeDetails.Profit = trade.profit;
            tradeDetails.Comment = trade.comment.Trim();
            tradeDetails.History = DateTime.Now - tradeDetails.OpenTime;

            //tradeDetails.RunningProfit = ????????

        }

        i++;
    }
}

Answer 1

您可以创建一个局部变量来跟踪运行利润，利用赋值操作返回所分配的值这一事实。

tradeDetails.RunningProfit = (runningProfit = runningProfit + trade.profit);