主题：关于XML的问题，初学，请发代码学习

如何提取文件名部分字符串的合集呢

比如

我要提取\fa piao\Jskp中

Dim db1 As WinForm.DropDownBox = e.Form.Controls("DropBox1")
Dim db2 As WinForm.DropDownBox = e.Form.Controls("DropBox2")
Dim dzml1 As String = db1.text
Dim dzml2 As String = db2.text
For Each f As String In FileSys.GetFiles(dzml2)
    Dim txt As String = FileSys.ReadAllText(f, Encoding.utf8)
    Dim xmlDoc As New System.XML.XmlDocument
    xmlDoc.Loadxml(txt.Trim)
    Dim ndList  = xmlDoc.GetElementsByTagName("mxxx")
    For Each dr As object In ndlist
        Dim ndr As Row = Tables("表b").addnew
        For Each n As System.XML.XmlNode In dr.childNodes
            output.show(n.Name & " = " & n.InnerText)
            If n.name = "fpdm" Then
                ndr("fa piao代码") = n.innertext
            End If
            If n.name = "fphm" Then
                ndr("fa piao号码") = val(n.innertext)
            End If
            If n.name = "gmfnsrsbh" Then
                ndr("纳税人识别号") = val(n.innertext)
            End If

        Next
    Next
Next

错误，

.NET Framework 版本：2.0.50727.9035
Foxtable 版本：2018.10.9.1
错误所在事件：窗口,窗口1,Button1,Click
详细错误信息：
根级别上的数据无效。 行 1，位置 1。