主题：这个表达式错在哪里啊？身份证

Select Case e.DataCol.name
    Case "证件号码"
        If e.DataRow.IsNull("证件号码") Then
            e.DataRow("原籍地址") = Nothing
            e.DataRow("性别") = Nothing
        Else
            e.DataRow("性别") = ReadSex(e.DataRow("证件号码"))
            Dim bm As String = e.DataRow("证件号码").SubString(0,6)
            Dim dr As DataRow = DataTables("身份证号码归属").Find("编码 = '" & bm & "'")
            If dr IsNot Nothing Then
                e.DataRow("原籍地址") = dr("地址")
            End If

        End If
End Select