Question

我发现这篇文章，我需要类似的东西

stackoverflow.com/questions/41282053/groupby-multiple-date-properties-by-month-and-year-in-linq/43112774#43112774

我需要按月和年分组，但同时我需要主要元素的属性，我无法访问

var departments = stops 
    .SelectMany(x => new[] { x.InitDate.Month, x.InitDate.Year }
    .Where(dt => dt != null).Select(dt => x.InitDate))
    .GroupBy(dt => new { dt.Month, dt.Year }) 
    .OrderBy(g => g.Key.Month)
    .ThenBy(g => g.Key.Year) 
    .Select(g => new 
    { 
        Key = g.Key.Month, 
        Año = g.Key.Year, 
        Duration = 0, 
        Count = g.Count() 
    });

我需要访问“stops.Duration”，但如果我这样做：.SelectMany(x => new[] { x.InitDate.Month, x.InitDate.Year, x.Duration }

它没有按月分组我

有人能帮助我吗？

对不起我的英文，非常感谢你

Answer 1

此代码应该：

var departments = stops 
    .Where(stop => stop.InitDate != null)
    .SelectMany(stop => new[] { Month = stop.InitDate.Month, Year = stop.InitDate.Year, Duration = stop.Duration })
    .GroupBy(dt => new { dt.Month, dt.Year }) 
    .OrderBy(g => g.Key.Month)
    .ThenBy(g => g.Key.Year) 
    .Select(g => new 
    { 
        Key = g.Key.Month, 
        Año = g.Key.Year, 
        Duration = g.Sum(v => v.Duration), 
        Count = g.Count() 
    });

选择持续时间，月份和年份组，并使用分组结果中的持续时间总和。

Answer 2

int Month = 0, Year= 0, Duration = 0;
var departments = stops 
    .Where(stop => stop.InitDate != null)
    .SelectMany(stop => new[] { Month = stop.InitDate.Month, Year = stop.InitDate.Year, Duration = stop.Duration })
    .GroupBy(dt => new { Month, Year }) 
    .OrderBy(g => g.Key.Month)
    .ThenBy(g => g.Key.Year) 
    .Select(g => new 
    { 
        Key = g.Key.Month, 
        Año = g.Key.Year, 
        Duration = g.Sum(v => Duration), 
        Count = g.Count() 
    });

对我来说，这是最终的解决方案

。用C＃选择很多

2 个答案: