ถามเกี่ยวกับการ create textfile บน desktop กับ ie mobile ค่ะ

using System;
using System.IO;
using System.Runtime.InteropServices;

namespace StorageCardInfo
{
    class Program
    {
        const ulong Megabyte = 1048576;
        const ulong Gigabyte = 1073741824;

        [DllImport("CoreDLL")]
        static extern int GetDiskFreeSpaceEx(
        string DirectoryName,
        out ulong lpFreeBytesAvailableToCaller,
        out ulong lpTotalNumberOfBytes,
        out ulong lpTotalNumberOfFreeBytes 
    );

    static void Main(string[] args)
    {
        DirectoryInfo root = new DirectoryInfo("\\");
        DirectoryInfo[] directoryList = root.GetDirectories();
        ulong FreeBytesAvailable;
        ulong TotalCapacity;
        ulong TotalFreeBytes;

        for (int i = 0; i < directoryList.Length; ++i)
        {
            if ((directoryList.Attributes & FileAttributes.Temporary) != 0)
            {
                GetDiskFreeSpaceEx(directoryList.FullName, out FreeBytesAvailable, out TotalCapacity, out TotalFreeBytes);
                Console.Out.WriteLine("Storage card name: {0}", directoryList.FullName);
                Console.Out.WriteLine("Available Bytes : {0}", FreeBytesAvailable);
                Console.Out.WriteLine("Total Capacity : {0}", TotalCapacity);
                Console.Out.WriteLine("Total Free Bytes : {0}", TotalFreeBytes);
            }
        }
    }
}

Private Sub WRITEFILESALES()

        Dim dt As New DataTable
        Dim strQ As String = ""
        strQ = "SELECT * FROM SALES WHERE RouteNo=" & Session.Contents("irouteno") & ""
        dt = GetData(strQ, "SALES.mdb")
        If dt.Rows.Count <= 0 Then
            Response.Write("<script language='javascript'>window.alert('ไม่มีข้อมูล!');</script>")
            Return

        End If
        '==============================================
        Dim rootDir As DirectoryInfo = New DirectoryInfo("\")
        Dim attrStorageCard As FileAttributes = (FileAttributes.Directory Or FileAttributes.Temporary)
        Dim fsi As FileSystemInfo
        Dim strpath As String = ""
        For Each fsi In rootDir.GetFileSystemInfos()
            Dim n As Integer = fsi.FullName.IndexOf("\")
            strpath = fsi.FullName.Substring(0, n)
        Next

        Dim sw As StreamWriter

        If File.Exists(strpath + txtsaveto.Text.Trim & Session.Contents("irouteno") & "Sales.txt") Then
            Response.Write("<script language='javascript'>window.alert('ชื่อไฟล์ซ้ำมีไฟล์ชื่อนี้อยู่แล้ว!');</script>")
            Return
        Else
            sw = File.CreateText(strpath + txtsaveto.Text.Trim & Session.Contents("irouteno") & "Sales.txt")
        End If

        Dim line As String = ""

        Try
            Dim SalesDate As String
            Dim RouteNo As String
            Dim InvNo As String
            Dim BookNo As String
            Dim CustCode As String
            Dim AmphorCode As String
            Dim BILLITEM As String
            Dim StockGroup As String
            Dim SHCode As String
            Dim Qty As String
            Dim Discount As String
            Dim Amount As String
            Dim PriceBig As String
            Dim PriceSmall As String
            Dim PVAT As String
            Dim LastUpdate As String
            Dim LastUser As String

            For i As Integer = 0 To dt.Rows.Count - 1
                SalesDate = CheckNull(dt.Rows(i).Item("SalesDate")) '8
                RouteNo = CheckNull(dt.Rows(i).Item("RouteNo")) '3
                InvNo = CheckNull(dt.Rows(i).Item("InvNo")) '6
                BookNo = CheckNull(dt.Rows(i).Item("BookNo")) '2
                CustCode = CheckNull(dt.Rows(i).Item("CustCode")) '8
                AmphorCode = CheckNull(dt.Rows(i).Item("AmphorCode")) '4
                BILLITEM = CheckNull(dt.Rows(i).Item("BILLITEM")) '3
                StockGroup = CheckNull(dt.Rows(i).Item("StockGroup"))  '4
                SHCode = CheckNull(dt.Rows(i).Item("SHCode")) '7
                Qty = CheckNull(dt.Rows(i).Item("Qty")) '7
                Discount = CheckNull(dt.Rows(i).Item("Discount")) '12
                Amount = CheckNull(dt.Rows(i).Item("Amount")) '12
                PriceBig = CheckNull(dt.Rows(i).Item("PriceBig")) '12
                PriceSmall = CheckNull(dt.Rows(i).Item("PriceSmall")) '12
                PVAT = CheckNull(dt.Rows(i).Item("PVAT")) '7
                LastUpdate = CheckNull(dt.Rows(i).Item("LastUpdate")) '13
                LastUser = CheckNull(dt.Rows(i).Item("LastUser")) '10

                line = SalesDate.PadRight(8, "") & RouteNo.PadRight(3, "") & _
                InvNo.PadRight(6, "") & BookNo.PadRight(2, "") & _
                CustCode.PadRight(8, "") & AmphorCode.PadRight(4, "") & _
                BILLITEM.PadRight(3, "") & StockGroup.PadRight(4, "") & _
                SHCode.PadLeft(7, "0") & Qty.PadLeft(7, "0") & _
                Discount.PadLeft(12, "0") & Amount.PadLeft(12, "0") & _
                PriceBig.PadLeft(12, "0") & PriceSmall.PadLeft(12, "0") & _
                PVAT.PadLeft(7, "0") & LastUpdate.PadRight(13, "") & _
                LastUser.PadRight(10, "")
                sw.WriteLine(line)
            Next
            sw.WriteLine("EOD")
            dt.Dispose()
            sw.Close()

        Catch ex As Exception
            Response.Write("<script language='javascript'>window.alert('ไม่สามารถดาวน์โหลดข้อมูลได้!');</script>")

            Exit Sub
        End Try
    End Sub

 '==============================================
        Dim rootDir As DirectoryInfo = New DirectoryInfo("\")
        Dim attrStorageCard As FileAttributes = (FileAttributes.Directory Or FileAttributes.Temporary)
        Dim fsi As FileSystemInfo
        Dim strpath As String = ""
        For Each fsi In rootDir.GetFileSystemInfos()
            Dim n As Integer = fsi.FullName.IndexOf("\")
            strpath = fsi.FullName.Substring(0, n)
        Next