参考代码
Dim t As Table = Tables("表C")
Dim ls As new List(Of Integer)
ls.add(0)
For Each r As Row In t.rows
Dim idx As Integer = val(r("层级"))
If idx = 0 Then
ls(0) = ls(0) + 1
For i As Integer = 1 To ls.count-1
ls(i) = 0
Next
Else
If idx >= ls.count Then
ls.add(0)
End If
ls(idx) = ls(idx) + 1
End If
Dim str As String = ""
For i As Integer = 0 To idx
str &= ls(i) & "."
Next
r("第二列") = str.trim(".")
Next