c# - 无法通过 linq 得到结果

Question

我有一张这样的桌子

   Id  TagNo  FromBay FromPanel FDevice FRef
    1   1000    A        B        C1     1
    2   1000    A        B        C1     2
    3   1000    A        B        C1     R2
    4   1000    A        B        C2     2
    5   1000    A        B        C2     3
    6   1000    A        B        C2     4

我想要这个

     TagNo  FromBay FromPanel FDevice  FRef
     1000    A        B        C1      1
                                       2
                                       R2
                               C2      2
                                       3
                                       4

这些值位于名为 cableDataTable 的数据表中

 var rows = cableDataTable.AsEnumerable()
                             .Select(x => new
                             {
                                 TagNo = x.Field<string>("TagNo"),
                                 FromBay = x.Field<string>("FromBay"),
                                 FromPanel = x.Field<string>("FromPanel"),         
                                 FDevice = x.Field<string>("FDevice"),                                

                                 FRef = x.Field<string>("FRef")                                                                  
                                 });

   var results = rows.GroupBy(row => new { row.FromBay, row.FromPanel, row.TagNo })
                        .OrderBy(g => g.Key.FromBay)
                        .ThenBy(g => g.Key.FromPanel)
                        .SelectMany(g => g.OrderBy(row => row.TagNo)
                         .Select((x, i) =>
                                new
                                {                                        
                                    TagNo = (i == 0) ? x.TagNo.ToString() : "",                                       
                                    FromBay = (i == 0) ? x.FromBay : "",
                                    FromPanel = (i == 0) ? x.FromPanel : "",
                                    FDevice = (i == 0) ? x.FDevice : "",
                                    FRef = x.FRef,                                        
                                })).ToList();  

但我明白了

                     TagNo  FromBay FromPanel FDevice  FRef
                      1000    A        B        C1      1
                                                        2
                                                        R2
                                                        2
                                                        3
                                                        4

我在一个论坛中找到了可能，但我不知道 .Select((x, i) 能做什么，我怎样才能得到我需要的结果。我找不到问题

Answer 1

我给你写了一个例子，以分层方式获取数据，我希望这就是你要找的。

var results = rows.GroupBy(row => new {row.FromBay, row.FromPanel, row.TagNo})
        .Select(x => new
            {
                x.Key.TagNo,
                x.Key.FromBay,
                x.Key.FromPanel,
                Devices =
                        rows.GroupBy(
                            row => new {row.FromBay, row.FromPanel, row.TagNo, row.FDevice})
                            .Where(f => f.Key.TagNo == x.Key.TagNo)
                            .Where(f => f.Key.FromBay == x.Key.FromBay)
                            .Where(f => f.Key.FromPanel == x.Key.FromPanel)
                            .Select(y => new
                                {
                                    y.Key.FDevice,
                                    FRef =
                                            rows.Where(r => r.TagNo == y.Key.TagNo)
                                                .Where(r => r.FromBay == y.Key.FromBay)
                                                .Where(r => r.FromPanel == y.Key.FromPanel)
                                                .Where(r => r.FDevice == y.Key.FDevice)
                                                .Select(i => i.FRef)
                                                .ToList()
                                }).ToList()
            }).ToList();

Answer 2

尝试这个：

 var results = rows.GroupBy(row => new { row.TagNo, row.FromBay, row.FromPanel})
                   .OrderBy(g => g.Key.TagNo)
                   .ThenBy(g => g.Key.FromBay)
                   .ThenBy(g => g.Key.FromPanel)
                   .Select((g,i) => new {
                                    key = g.Key,i,              
                                    sub = g.GroupBy(x=>x.FDevice).OrderBy(g=>g.Key)
                                           .Select(g=>g.Select((x,j)=>new{x,j}))
                                   })                               
                   .SelectMany(e=> e.sub, (e,c)=> new {
                                TagNo = e.i == 0 ? e.key.TagNo.ToString() : "",
                                FromBay = e.i == 0 ? e.key.FromBay : "",
                                FromPanel = e.i == 0 ? e.key.FromPanel : "",
                                FDevice = c.j == 0 ? c.x.FDevice : "",
                                FRef = c.x.FRef,
                               });