Question

好的，我知道这里有很多帖子，但我已经尝试解决这个问题几个小时了，我的大脑完全没了。

这是事情

我有一个包含3个属性（数量，服务，名称）的对象列表

我希望列表中的所有名称和服务（有点交叉连接）和相应行的分组数量。不清楚我猜

数量服务名称
  3 Srv2 Bob
  4 Srv2 Paul
  2 Srv1 Paul
  1 Srv2尼克

我想作为输出
所有服务以及所有名称和相应数量（如果没有则为0）

Srv1 Paul 2
Srv1 Bob 0
Srv1尼克0
Srv2 Paul 4
Srv2 Bob 3
Srv2 Nick 1

这是我到目前为止所获得的，但我甚至没有得到预期的结果而且我确信有一种非常简单的方法可以实现我想要的......我会受到一点帮助......

谢谢

    Dim services = (From a In interventions Select New With {.Service = a.Service}).Distinct()
    Dim months = (From b In interventions Select New With {.Month = b.DateHeureIntervention.Month}).Distinct()

    'Dim query = (From s In services _
    '             From m In months _
    '             From i In interventions.Where(Function(x) x.Service = s.Service And x.DateHeureIntervention.Month = m.Month).DefaultIfEmpty(New Intervention()) _
    '             Select New ChartItem With {.Service = s.Service, _
    '                                        .Name = MonthName(m.Month), _
    '                                        .Quantite = i.Quantite}).ToList()

    'Return (From q In query _
    '       Group By srv = q.Service, n = q.Name Into Group _
    '       Select New ChartItem With {.Name = n, _
    '                                  .Service = srv, _
    '                                  .Quantite = Group.Sum(Function(i) i.Quantite)}).ToList()


    Dim q = (From i In interventions _
            Group Join s In services On s.Service Equals i.Service Into si = _
            Group Join m In months On m.Month Equals i.DateHeureIntervention.Month _
            From x In si.DefaultIfEmpty() _
            Group By m = i.DateHeureIntervention.Month, srv = i.Service Into Group _
            Select New ChartItem With {.Service = srv, _
                                       .Name = MonthName(m), _
                                       .Quantite = Group.Sum(Function(y) y.i.Quantite)}).ToList()

    Return q

Answer 1

我在这里得到的是我的结果，肯定有更好的方法，但无论如何，它有效

    Dim months As List(Of Integer) = (From b In interventions Select b.DateHeureIntervention.Month).Distinct().ToList()
    Dim services As List(Of String) = (From c In interventions Select c.Service).Distinct().ToList()

    Dim q = (From s In services _
             From m In months _
             Select New ChartItem With {.Name = MonthName(m), _
                                        .Service = s, _
                                        .Quantite = (From i In AccesDonneesHelper.GetInterventionsDetails() _
                                                     Where i.Service = s And i.DateHeureIntervention.Month = m _
                                                     Select i.Quantite).Sum()}).ToList()

问题VB.NET LINQ Group加入

1 个答案: