C# 使用LINQ求和属性

最后一行的语法不正确。是否可以这样做，否则我将不得不为此属性编写查询以计算总和

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谢谢

您考虑过扩展方法吗？您提供总和功能的地方。

您考虑过扩展方法吗？这里提供了求和功能。

顺便说一句，Count还支持谓词参数：

因此，您可以：

DealsThisMonthOpen = deals.Where(deal => deal.DateCreated.Month == date.Month && deal.DealStatus == "Open").Count(),
DealsThisMonthLost = deals.Where(deal => deal.DateCreated.Month == date.Month && deal.DealStatus == "Lost").Count(),
DealsThisMonthWon = deals.Where(deal => deal.DateCreated.Month == date.Month && deal.DealStatus == "Won").Count(),
DealsThisMonth = DealsThisMonthOpen + DealsThisMonthLost + DealsThisMonthWon;

顺便说一句，Count还支持谓词参数：

因此，您可以：

DealsThisMonthOpen = deals.Where(deal => deal.DateCreated.Month == date.Month && deal.DealStatus == "Open").Count(),
DealsThisMonthLost = deals.Where(deal => deal.DateCreated.Month == date.Month && deal.DealStatus == "Lost").Count(),
DealsThisMonthWon = deals.Where(deal => deal.DateCreated.Month == date.Month && deal.DealStatus == "Won").Count(),
DealsThisMonth = DealsThisMonthOpen + DealsThisMonthLost + DealsThisMonthWon;

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也许我遗漏了什么，但这肯定有用

Count方法返回int，因此DealsThisMonthOpen、DealsThisMonthLost和DealsThisMonthWon都是整数值。DealsThisMonth就是这三个整数值的总和

您还可以使它更干净一点，除非以后需要三个不同的值：

var a = deals.Count(deal => deal.DateCreated.Month == date.Month && deal.DealStatus == "Open"),
var b = deals.Count(deal => deal.DateCreated.Month == date.Month && deal.DealStatus == "Lost"),
var c = deals.Count(deal => deal.DateCreated.Month == date.Month && deal.DealStatus == "Won"),

new foobar
{
    DealsThisMonthOpen = a,
    DealsThisMonthLost = b,
    DealsThisMonthWon = c,
    DealsThisMonth = a + b + c
};

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也许我遗漏了什么，但这肯定有用

Count方法返回int，因此DealsThisMonthOpen、DealsThisMonthLost和DealsThisMonthWon都是整数值。DealsThisMonth就是这三个整数值的总和

您还可以使它更干净一点，除非以后需要三个不同的值：

var a = deals.Count(deal => deal.DateCreated.Month == date.Month && deal.DealStatus == "Open"),
var b = deals.Count(deal => deal.DateCreated.Month == date.Month && deal.DealStatus == "Lost"),
var c = deals.Count(deal => deal.DateCreated.Month == date.Month && deal.DealStatus == "Won"),

new foobar
{
    DealsThisMonthOpen = a,
    DealsThisMonthLost = b,
    DealsThisMonthWon = c,
    DealsThisMonth = a + b + c
};