使用LINQ to SQL计算运行总数

本文关键字：运行 计算 SQL LINQ to 使用 | 更新日期: 2023-09-27 18:11:36

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。我已经添加了一个Running pip列，并一直试图弄清楚如何正确填充这个列。我通过网络搜索找到了几种方法，但这些方法都不适合我的特定设置。大多数时候，我都陷入了一个无休止的循环。我希望"运行点数"列是累积的，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

下面是代码摘要。我希望有人能建议如何修复这段代码与任何相关的信息，以帮助我实现这一点:

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++;
    }
}

使用LINQ to SQL计算运行总数

您可以创建一个局部变量来跟踪运行利润，利用赋值操作返回被赋值的事实。

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

这是一个一般的想法-您应该能够根据您的需要采用它:

class Trade {
    public DateTime CloseTime { get; set; }
    public decimal Profit { get; set; }
}
class TradeWithRunningProfit : Trade {
    public decimal RunningProfit { get; set; }
}
class Program {
    static IEnumerable<TradeWithRunningProfit> GetRunningProfits(IEnumerable<Trade> rows) {
        decimal running_profit = 0;
        return
            from row in rows
            select new TradeWithRunningProfit {
                CloseTime = row.CloseTime,
                Profit = row.Profit,
                RunningProfit = (running_profit += row.Profit)
            };
    }
    static void Main(string[] args) {
        var rows = new[] {
            new Trade { CloseTime = new DateTime(11,10,09), Profit = 10},
            new Trade { CloseTime = new DateTime(11,10,10), Profit = 20},
            new Trade { CloseTime = new DateTime(11,10,11), Profit = 15},
        };
        foreach (var row_with_running_profit in GetRunningProfits(rows)) {
            Console.WriteLine(
                "{0}'t{1}'t{2}",
                row_with_running_profit.CloseTime,
                row_with_running_profit.Profit,
                row_with_running_profit.RunningProfit
            );
        }
    }
}
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