Richtextbox Savefile and UTF-8

I'm just getting starting working with VB.NET -- mostly because I have need for using UTF-8 encodings within an application. However, I see that the Richtextbox.SaveFile method doesn't include a UTF-8 encoding option. I'm sure that this must be available (since V. 3 of the RichEdit dll allows for UTF-8) or there must be a way to do what I'm looking to do. Basically, I just need to be able to save files in UTF8 and load files in UTF8. Can anyone get me pointed in the right direction.

Thanks

Ok -- Maybe this question is more difficult than I thought. How about this then. In VB6, I'd re-written the LoadFile and SaveFile functions so that I could load UTF-8 text into the control. To do this, I had to re-write the Callbacks. I've tried to translate them, but I'm not seeing any data. I'm sure its because I'm not understanding how the datatypes should be working. Here is the form and Module code that I'm using. Can anyone figure out how this might work? I can't get the ReadFile function to work and can't figure out how to pass a FileStream handle into the Callback (which would probably work better).

Thanks

Form Code

VB Code:

Option Strict On
Option Explicit On 
Imports System.Runtime.InteropServices
 
Friend Class Form1
    Inherits System.Windows.Forms.Form
'Region Code was Delete to save space
    Public Enum ERECFileTypes
        SF_TEXT = &H1s
        SF_RTF = &H2s
        SF_UNICODE = &H10s
    End Enum
 
 
 
    Private m_hWnd As IntPtr
 
 
 
    Public Function LoadFromFile(ByVal sFile As String, ByVal eType As Form1.ERECFileTypes) As Boolean
        Dim hFile As Integer
        Dim tOF As OFSTRUCT = New OFSTRUCT()
        Dim tStream As EDITSTREAM = New EDITSTREAM()
        Dim lR As Integer
        Dim FF As Integer
 
        tOF.Initialize()
 
        m_hWnd = RichTextBox1.Handle
        hFile = OpenFile("c:\documents and settings\reeset\desktop\finished_ebsco.mrk", tOF, OF_READ)
 
 
 
        If (hFile <> 0) Then
            tStream.dwCookie = hFile
            'UPGRADE_WARNING: Add a delegate for AddressOf LoadCallBack Click for more: 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="vbup1048"'
            tStream.pfnCallback = AddressOf LoadCallBack
            tStream.dwError = 0
            FileMode = True
 
            ' The text will be streamed in though the LoadCallback function
            'Dim lParam As System.IntPtr
            'Marshal.StructureToPtr(tStream, lParam, True)
            lR = SendMessage(m_hWnd, EM_STREAMIN, eType, tStream)
            MsgBox("called")
            LoadFromFile = (lR <> 0)
            FileMode = False
 
 
 
 
            CloseHandle(hFile)
 
        End If
 
        MsgBox("finished")
 
    End Function
 
 
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
 
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If LoadFromFile("c:\documents and settings\reeset\desktop\finished_ebsco.mrk", ERECFileTypes.SF_TEXT) = False Then
            MsgBox("nothing loaded")
        End If
    End Sub

Module Code

VB Code:

Option Strict Off
Option Explicit On 
Imports System.Runtime.InteropServices
 
Module Module1
    <StructLayout(LayoutKind.Sequential)> _
    Public Structure EDITSTREAM
        <MarshalAs(UnmanagedType.I4)> Dim dwCookie As Integer ' /* user value passed to callback as first parameter */
        <MarshalAs(UnmanagedType.I4)> Dim dwError As Integer ' /* last error */
        Dim pfnCallback As LoadCallBackDelegate 'EDITSTREAMCALLBACK
    End Structure
 
 
 
    Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, ByRef lParam As EDITSTREAM) As Integer
    Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As IntPtr, ByVal wMsg As Integer, ByVal wParam As Integer, ByRef lParam As EDITSTREAM) As Integer
    Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (ByVal lpvDest As Integer, ByVal lpvSource As Integer, ByVal cbCopy As Integer)
    Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (ByVal lpvDest As Integer, ByVal lpvSource As IntPtr, ByVal cbCopy As Integer)
    Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (ByVal lpvDest As String, ByVal lpvSource As IntPtr, ByVal cbCopy As Integer)
    Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (ByVal lpvDest As IntPtr, ByVal lpvSource As Integer, ByVal cbCopy As Integer)
    Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (ByVal lpvDest As String, ByVal lpvSource As String, ByVal cbCopy As Integer)
 
    Public Structure OVERLAPPED
        Dim Internal As Integer
        Dim InternalHigh As Integer
        Dim offset As Integer
        Dim OffsetHigh As Integer
        Dim hEvent As Integer
    End Structure
    Public Const OFS_MAXPATHNAME As Short = 128
 
    <StructLayout(LayoutKind.Sequential)> _
        Public Structure OFSTRUCT
        Dim cBytes As Byte
        Dim fFixedDisk As Byte
        Dim nErrCode As Short
        Dim Reserved1 As Short
        Dim Reserved2 As Short
        <MarshalAs(UnmanagedType.ByValArray, SizeConst:=OFS_MAXPATHNAME)> _
        Dim szPathName() As Byte
 
        Public Sub Initialize()
            ReDim szPathName(OFS_MAXPATHNAME)
        End Sub
 
    End Structure
    ' Streaming support:
    'UPGRADE_ISSUE: Declaring a parameter 'As Any' is not supported. Click for more: 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="vbup1016"'
    Public Declare Function WriteFile Lib "kernel32" (ByVal hFile As Integer, ByRef lpBuffer As Integer, ByVal nNumberOfBytesToWrite As Integer, ByRef lpNumberOfBytesWritten As Integer, ByVal lpOverlapped As Integer) As Integer 'lpOverlapped As OVERLAPPED) As Long
    'UPGRADE_WARNING: Structure OFSTRUCT may require marshalling attributes to be passed as an argument in this Declare statement. Click for more: 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="vbup1050"'
    Public Declare Function OpenFile Lib "kernel32" (ByVal lpFileName As String, ByRef lpReOpenBuff As OFSTRUCT, ByVal wStyle As Integer) As Integer
    'UPGRADE_ISSUE: Declaring a parameter 'As Any' is not supported. Click for more: 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="vbup1016"'
    Public Declare Function ReadFile Lib "kernel32" (ByVal hFile As Integer, ByRef lpBuffer As String, ByVal nNumberOfBytesToRead As Integer, ByRef lpNumberOfBytesRead As Integer, ByVal lpOverlapped As Integer) As Integer 'lpOverlapped As OVERLAPPED) As Long
    Public Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Integer) As Integer
    Public Const OF_CANCEL As Short = &H800S
    Public Const OF_CREATE As Short = &H1000S
    Public Const OF_DELETE As Short = &H200S
    Public Const OF_EXIST As Short = &H4000S
    Public Const OF_PARSE As Short = &H100S
    Public Const OF_PROMPT As Short = &H2000S
    Public Const OF_REOPEN As Short = &H8000S
    Public Const OF_SHARE_COMPAT As Short = &H0S
    Public Const OF_SHARE_DENY_NONE As Short = &H40S
    Public Const OF_SHARE_DENY_READ As Short = &H30S
    Public Const OF_SHARE_DENY_WRITE As Short = &H20S
    Public Const OF_SHARE_EXCLUSIVE As Short = &H10S
    Public Const OF_VERIFY As Short = &H400S
    Public Const OF_WRITE As Short = &H1S
    Public Const OF_READ As Short = &H0S
    Public Const OF_READWRITE As Short = &H2S
 
 
 
    ' /* stream formats */
 
    'Public Const SF_TEXT = &H1
    'Public Const SF_RTF = &H2
    Public Const WM_USER As Short = &H400S
    Public Const SF_RTFNOOBJS As Short = &H3S ' /* outbound only */
    Public Const SF_TEXTIZED As Short = &H4S ' /* outbound only */
    Public Const SF_UNICODE As Short = &H10S ' /* Unicode file of some kind */
    Public Const EM_STREAMIN As Integer = (WM_USER + 73)
    Public Const EM_STREAMOUT As Integer = (WM_USER + 74)
    ' /* EM_SETCHARFORMAT wParam masks */
    Public Const SCF_SELECTION As Integer = &H1
    Public Const SCF_WORD As Integer = &H2
    Public Const SCF_DEFAULT As Integer = &H0 '// set the default charformat or paraformat
    Public Const SCF_ALL As Integer = &H4 '// not valid with SCF_SELECTION or SCF_WORD
    Public Const SCF_USEUIRULES As Integer = &H8 '// modifier for SCF_SELECTION; says that
    ' // the format came from a toolbar, etc. and
    ' // therefore UI formatting rules should be
    ' // used instead of strictly formatting the
    ' // selection.
 
    Private m_sText As String
    Private m_lPos As Integer
    Private m_lLen As Integer
    Private m_bFileMode As Boolean
    Private m_lObj As Integer
    Public Delegate Function LoadCallBackDelegate(ByVal dwCookie As Integer, ByVal lPtrPbBuff As IntPtr, ByVal cb As Integer, ByVal pcb As Integer) As Integer
 
 
    Public Property FileMode() As Boolean
        Get
            FileMode = m_bFileMode
        End Get
        Set(ByVal Value As Boolean)
            m_bFileMode = Value
            m_lPos = 0
            m_lLen = -1
        End Set
    End Property
 
 
    Public Function LoadCallBack(ByVal dwCookie As Integer, ByVal lPtrPbBuff As IntPtr, ByVal cb As Integer, ByVal pcb As Integer) As Integer
        Dim sBuf As String
        Dim b() As Byte
        Dim lLen As Integer
        Dim lRead As Integer
 
        If (m_bFileMode) Then
            ReadFile(dwCookie, sBuf, cb, pcb, 0)
 
            MsgBox(System.Text.Encoding.UTF8.GetString(b))
 
            'ReDim lPtrPbBuff(4094 - 1)
            'ReadFile(dwCookie, lPtrPbBuff, cb, pcb, 0)
 
 
            'MsgBox(System.Text.Encoding.UTF8.GetString(lPtrPbBuff))
 
 
            'CopyMemory(lRead, lPtrPbBuff(0), 4)
 
            If (lRead < cb) Then
                ' Complete:
                Return 0
            Else
                ' More to read:
                Return 0
            End If
            m_lPos = m_lPos + lRead
 
 
        
 
        End If
 
    End Function