主题：根据单列字段字符长度生成目录树

Dim str As String = "1000000000003"
Dim ns As String = ""
ns = str.SubString(0, 4)
For i As Integer = 4 To str.length - 1
    If (i - 4) Mod 3 = 0 Then
        ns &= "," & str(i)
    Else
        ns &= str(i)
    End If
Next

msgbox(ns)