すいません、VB４しかやってないんです、VBAはやったけど（ぼそ）　チラシの裏だって立派な書き込み空間なんだからねっ！資源の有効活用なんだからねっ！とか偉そうに言ってるけど、実は色々と書き残したいだけ

Module Module1

 
     Sub Main()

 
         Dim samples As New List(Of SampleRecord)
         Dim rnd As New Random

 
         Dim KeysCount = rnd.Next(1, 23)

 
         Console.WriteLine("{0} 件キー", KeysCount)

 
         For x As Integer = 1 To KeysCount
             For f As Integer = 1 To rnd.Next(1, 55)
                 samples.Add(New SampleRecord With {
                                     .Key1 = x.ToString("KeyA-000"),
                                     .Key2 = x.ToString("KeyB-000"),
                                     .Key3 = x.ToString("KeyC-000"),
                                     .Data1 = f.ToString("DataA-00"),
                                     .Data2 = f.ToString("DataB-00"),
                                     .Data3 = f.ToString("DataC-00")
                                     })
             Next
         Next

 
         Dim c = From x As SampleRecord In samples
                 Group x By x.Key1, x.Key2, x.Key3
                 Into Datas = Group
                 Select New Hoge With {
                     .Key1 = Key1,
                     .Key2 = Key2,
                     .Key3 = Key3,
                     .Datas = Datas.Select(Function(f)
                                               Return New DetailData With {
                                                                 .Data1 = f.Data1,
                                                                 .Data2 = f.Data2,
                                                                 .Data3 = f.Data3
                                                                }
                                           End Function).ToList
                     }

 
         c.ToList.ForEach(Function(x)
                              Console.WriteLine("{0}-{1}-{2}-{3}", x.Key1, x.Key2, x.Key3, x.Datas.Count)
                          End Function)

 
         Console.ReadKey()
     End Sub

 

End Module

 

Public Class SampleRecord
     Property Key1 As String
     Property Key2 As String
     Property Key3 As String
     Property Data1 As String
     Property Data2 As String
     Property Data3 As String

End Class

 

Public Class DetailData
     Property Data1 As String
     Property Data2 As String
     Property Data3 As String

End Class

 

Public Class Hoge
     Property Key1 As String
     Property Key2 As String
     Property Key3 As String

 
     Property Datas As List(Of DetailData)

End Class