在For循环中传递键值对

Question

如何将整个KeyValuePair传递给For循环？

 Dim grouped As New Dictionary(Of [String], List(Of DataRow))()
    For index = grouped.Count-1 To 0 Step -1

    'How do I pass the entire KeyValuePair to the PopulateData function?
    PopulateData(????)
    Next

Answer 1

你可以这样做，例如：

Sub Main()
  Dim grouped As New Dictionary(Of [String], List(Of DataRow))()
  For index = grouped.Count - 1 To 0 Step -1
    PopulateData(New KeyValuePair(Of String,
      List(Of DataRow))(grouped.Keys(index), grouped.Values(index)))
  Next
End Sub

Sub PopulateData(kv As KeyValuePair(Of String, List(Of DataRow)))
End Sub

但是，您正在以这种方式将.NET框架扩展到限制，字典不应该向前或向后迭代。即使您决定迭代它，您的代码也不应该依赖于元素的顺序，否则它可能会在以后中断。