Question

这是我的代码中的数据表：

PackID   PackName       FilterID      SystemID    SystemName
 18       ThirdRep       0             5           ABC
 18       ThirdRep       1             5           ABC
 18       ThirdRep       3             3           XYZ
 17       SecondRep      0             5           ABC

我需要对Package下的所有系统进行分组，并将Linq中系统下的所有过滤器分组。我想将这些数据转换如下。

包的集合（预期结果的一个例子）：

PackageID  :17
PackName   :SecondRep     
SystemCollection [ SystemID:5 , SystemName : ABC, FilterCollection [FilterID:1,FilterID:0 ] ]


PackageID  :18
PackName   :ThirdRep      
SystemCollection [ SystemID:5 , SystemName : ABC, FilterCollection [FilterID:0 ] ]

我的代码：

var groupedData = from b in dataset.Tables[0].AsEnumerable()
                  group b by new
                  {
                      PackageID = b.Field<Int32>("PackageID"),
                      PackageName = b.Field<string>("PackageName"),
                  } into g
                  select new ReportPackage
                  {
                      PackageId = g.Key.PackageID,
                      PackageName = g.Key.PackageName,
                      SystemCollection = g.Select(c => new ReportSystem
                      {
                          SystemId = c.Field<int>("SystemID"),
                          SystemName = c.Field<string>("SystemName"),
                          FilterCollection = g.Select(b => new ReportFilter
                          {
                              FilterId = b.Field<int>("FilterID"),
                          }).ToList()
                      }).GroupBy(x => x.SystemId).Select(v => v.First()).ToList()
                  };

以上代码对我没什么帮助。无论系统ID如何，所有过滤器都会添加到集合中。

Answer 1

您应首先按SystemID和SystemName对过滤器进行分组，然后执行选择，而不是相反。

尝试：

var groupedData = from b in dataset.Tables[0].AsEnumerable()
                  group b by new
                  {
                      PackageID = b.Field<int>("PackageID"),
                      PackageName = b.Field<string>("PackageName"),
                  } into g
                  select new ReportPackage
                  {
                      PackageId = g.Key.PackageID,
                      PackageName = g.Key.PackageName,
                      SystemCollection = (from e in g
                                          group e by new
                                          {
                                              SystemID = b.Field<int>("SystemID"),
                                              SystemName = b.Field<string>("SystemName")
                                          } into fg
                                          select new ReportSystem
                                          {
                                              fg.SystemID,
                                              fg.SystemName,
                                              FilterCollection = fg.Select(f => new ReportFilter
                                              {
                                                  FilterID = f.Field<int>("FilterID")
                                              }                                                 
                                          }).ToList()
                  }

在Linq中嵌套分组

1 个答案: