关于集合乱序的有关问题

关于集合乱序的问题
目前遇到一个问题，如何在知道集合元素Index的情况下，获取对应元素的key

VB.NET code

    Public Function 乱序(ByRef 集合 As Microsoft.VisualBasic.Collection) As Microsoft.VisualBasic.Collection        Dim i, t, LBnd, UBnd As Integer        Dim 临时键值 As String        Dim 临时元素 As Object        Dim 返回集合 As Microsoft.VisualBasic.Collection        LBnd = 1 : UBnd = 集合.Count : Randomize()        For i = LBnd To UBnd            t = Int((UBnd - LBnd + 1) * Rnd() + LBnd)            临时元素 = 集合(t)            临时键值 = 集合(t).GetHashCode '如何获取元素键值？？？            If i = 1 Then MsgBox(临时键值)            集合.Remove(t)            集合.Add(临时元素, 临时键值)            UBnd = UBnd - 1        Next        返回集合 = 集合        Return 返回集合    End Function

VB.NET code

Public Function 乱序(ByRef 集合 As Microsoft.VisualBasic.Collection) As Microsoft.VisualBasic.Collection    Dim list As New List(Of Object)()    For Each item As Object In 集合        list.Add(item)    Next    Dim rndlist = list.Select(Function(x) Return New KeyValuePair(Of String, Of Object)(Guid.NewGuid().ToString(), x)).OrderBy(Function(x) Return x.Key).ToList()    Dim 返回集合 As Microsoft.VisualBasic.Collection    rndlist.ForEach(Function(x) 返回集合.Add(x))    Return 返回集合End Function