主题：[求助]目录树级点代码

以下代码主要目录获取各个节点的级点，但不能达能预期目的。求助！

        For Each nd As WinForm.TreeNode In tv.AllNodes
            Dim jm As String = Format(nd.Index + 1,"00")
            Do
                If nd.ParentNode Is Nothing Then
                    Exit Do
                Else
                    nd = nd.ParentNode
                    jm = Format(nd.Index + 1,"00") & "." & jm
                End If
            Loop
            MessageBox.Show(nd.Name & "|" & jm)

        Next