Question

我按天数对一堆文件进行分组（确定文件何时退出）。现在我想从分组中检索属性列表：

    Dim agencyDocumentBatches As List(Of AgencyDocumentBatch) = _agencyDocumentBatchesData.ExecuteQuery(queryParameter, _context.DatabaseName)

    Dim documentBatchesGroupedByDay As IEnumerable(Of IGrouping(Of Integer, List(Of AgencyDocumentBatch))) =
            agencyDocumentBatches.GroupBy(Function(d) d.Days)

    For Each documentBatchGroup As IGrouping(Of Integer, List(Of AgencyDocumentBatch)) In documentBatchesGroupedByDay

    Dim addBookingDocumentsParams As New AddBookingDocumentsParams() With
    {
        .BCode = bCode,
        .DueDate = quote.DepartureDate.AddDays(-documentBatchGroup.Key),     'Key = Days before/after departure
        .Documents = documentBatchGroup.Select(Function(d) d.DocumentName).ToList
    }
    _documentDatesData.ExecuteQuery(addBookingDocumentsParams, _context.DatabaseName)
    Next

但是我看到那里没有定义d.DocumentName，它认为d是一个Collection。我认为迭代分组会让我们自己访问元素，我错了吗？

Public Class AgencyDocumentBatch

        Public Property ID As Integer

        Public Property DocumentID As Integer

        Public Property Days As Integer

        Public Property AfterDeparture As Boolean

        Public Property DocumentName As String

    End Class

Answer 1

这里的模拟，我希望，是你需要的（一些属性被省略）：

Module Module1

    Sub Main()

        Dim list = New List(Of AgencyDocumentBatch) From {
            New AgencyDocumentBatch With {.Days = 1, .DocumentName = "Doc1"},
            New AgencyDocumentBatch With {.Days = 2, .DocumentName = "Doc2"},
            New AgencyDocumentBatch With {.Days = 1, .DocumentName = "Doc3"},
            New AgencyDocumentBatch With {.Days = 2, .DocumentName = "Doc4"}
        }

        Dim documentBatchesGroupedByDay = From l In list
                                          Group l By l.Days Into Group

        For Each doc In documentBatchesGroupedByDay
            Dim proxy = New AddBookingDocumentsParams With
            {
                .Documents = doc.Group.Select(Function(a) a.DocumentName).ToList()
            }
        Next

    End Sub

End Module


Class AddBookingDocumentsParams
    Property Documents As List(Of String)
End Class

Public Class AgencyDocumentBatch
    Public Property Days As Integer
    Public Property DocumentName As String
End Class

Answer 2

我找到了另一种没有别名的解决方案：

For Each documentBatchGroup As IGrouping(Of Integer, List(Of AgencyDocumentBatch)) In documentBatchesGroupedByDay

        Dim addBookingDocumentsParams As New AddBookingDocumentsParams() With
        {
            .BCode = bCode,
            .DueDate = quote.DepartureDate.AddDays(-documentBatchGroup.Key),     'Key = Days before/after departure
            .Documents = documentBatchGroup(documentBatchGroup.Key).Select(Function(d) d.DocumentName).ToList
        }
        _documentDatesData.ExecuteQuery(addBookingDocumentsParams, _context.DatabaseName)

        Next

从IGrouping中选择属性列表

2 个答案: