主题：[求助]如何根据线路，拆分路段

 线路：北京-淮安-江阴-上海，拆分为路段：北京-淮安，淮安-江阴，江阴-上海

用以下代码：

Dim dt1 As DataTable = DataTables("表A")
Dim dt2 As DataTable = DataTables("表B")
For Each dr As DataRow In dt1.Select("")
    Dim ls1 As new List(Of String)
    ls1.AddRange(dr("线路").split("-"))
    For i As Integer = 1 To ls1.count -1
        Dim ndr As DataRow = dt2.AddNew
        ndr("日期") = dr("日期")
        ndr("线路") = dr("线路")
        ndr("路段") = ls1(0) & "-" & ls1(i)
    Next
Next

拆分后路段：北京-淮安，北京-江阴，北京-上海，如何修改此代码，拆分路段为：北京-淮安，淮安-江阴，江阴-上海