一個完整的COM通訊類

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/Files/msnadair/rs232.rar
(解壓密碼:msnadair)

Imports System.Runtime.InteropServices
Imports System.Text
Imports System.Threading
Imports System.ComponentModel
Imports System.IO

 

#Region "RS232"
Public Class Rs232 : Implements IDisposable
   '===================================================
   '
   ' Module    : Rs232
   ' Description  : Class for handling RS232 comunication with VB.Net
   ' Created    : 10/08/2001 - 8:45:25
   ' Author    : Corrado Cavalli 
   '   '    '=================================================== 
   '// Class Members  
 Private mhRS As IntPtr = New IntPtr(0)   '// Handle to Com Port         
   Private miPort As Integer = 1   '//  Default is COM1 
   Private miTimeout As Int32 = 70   '// Timeout in ms
   Private miBaudRate As Int32 = 9600
   Private meParity As DataParity = 0
   Private meStopBit As DataStopBit = 0
   Private miDataBit As Int32 = 8
   Private miBufferSize As Int32 = 512   '// Buffers size default to 512 bytes
   Private mabtRxBuf As Byte()   '//  Receive buffer 
    Private meMode As Mode  '//  Class working mode 

 Private moThreadTx As Thread
 Private moThreadRx As Thread
    Private moEvents As Thread

   Private miTmpBytes2Read As Int32
   Private meMask As EventMasks
   Private mbDisposed As Boolean
 Private mbUseXonXoff As Boolean
 Private mbEnableEvents As Boolean
 Private miBufThreshold As Int32 = 1
 Private muOvlE As OVERLAPPED
 Private muOvlW As OVERLAPPED
 Private muOvlR As OVERLAPPED
 Private mHE As GCHandle
 Private mHR As GCHandle
 Private mHW As GCHandle
 '----------------------------------------------------------------------------------------

#Region "Enums"
 '// Parity Data
 Public Enum DataParity
  Parity_None = 0
        Parity_Odd
  Parity_Even
  Parity_Mark
 End Enum
 '// StopBit Data
 Public Enum DataStopBit
  StopBit_1 = 1
  StopBit_2
 End Enum
 <Flags()> Public Enum PurgeBuffers
  RXAbort = &H2
  RXClear = &H8
  TxAbort = &H1
  TxClear = &H4
 End Enum
 Private Enum Lines
  SetRts = 3
  ClearRts = 4
  SetDtr = 5
  ClearDtr = 6
  ResetDev = 7   ' // Reset device if possible
  SetBreak = 8   ' // Set the device break line.
  ClearBreak = 9   ' // Clear the device break line.
 End Enum
 '// Modem Status
 <Flags()> Public Enum ModemStatusBits
  ClearToSendOn = &H10
  DataSetReadyOn = &H20
  RingIndicatorOn = &H40
  CarrierDetect = &H80
 End Enum
 '// Working mode
 Public Enum Mode
  NonOverlapped
  Overlapped
 End Enum
 '// Comm Masks
 <Flags()> Public Enum EventMasks
  RxChar = &H1
  RXFlag = &H2
  TxBufferEmpty = &H4
  ClearToSend = &H8
  DataSetReady = &H10
  CarrierDetect = &H20
  Break = &H40
  StatusError = &H80
  Ring = &H100
 End Enum

#End Region
#Region "Structures"
 <StructLayout(LayoutKind.Sequential, Pack:=1)> Private Structure DCB
  Public DCBlength As Int32
  Public BaudRate As Int32
  Public Bits1 As Int32
  Public wReserved As Int16
  Public XonLim As Int16
  Public XoffLim As Int16
  Public ByteSize As Byte
  Public Parity As Byte
  Public StopBits As Byte
  Public XonChar As Char
  Public XoffChar As Char
  Public ErrorChar As Char
  Public EofChar As Char
  Public EvtChar As Char
  Public wReserved2 As Int16
 End Structure
 <StructLayout(LayoutKind.Sequential, Pack:=1)> Private Structure COMMTIMEOUTS
  Public ReadIntervalTimeout As Int32
  Public ReadTotalTimeoutMultiplier As Int32
  Public ReadTotalTimeoutConstant As Int32
  Public WriteTotalTimeoutMultiplier As Int32
  Public WriteTotalTimeoutConstant As Int32
 End Structure
    <StructLayout(LayoutKind.Sequential, Pack:=8)> Private Structure COMMCONFIG
        Public dwSize As Int32
        Public wVersion As Int16
        Public wReserved As Int16
        Public dcbx As DCB
        Public dwProviderSubType As Int32
        Public dwProviderOffset As Int32
        Public dwProviderSize As Int32
        Public wcProviderData As Int16
    End Structure
    <StructLayout(LayoutKind.Sequential, Pack:=1)> Public Structure OVERLAPPED
        Public Internal As Int32
        Public InternalHigh As Int32
        Public Offset As Int32
        Public OffsetHigh As Int32
        Public hEvent As IntPtr
    End Structure
    <StructLayout(LayoutKind.Sequential, Pack:=1)> Private Structure COMSTAT
        Dim fBitFields As Int32
        Dim cbInQue As Int32
        Dim cbOutQue As Int32
    End Structure

#End Region
#Region "Constants"
 Private Const PURGE_RXABORT As Integer = &H2
 Private Const PURGE_RXCLEAR As Integer = &H8
 Private Const PURGE_TXABORT As Integer = &H1
 Private Const PURGE_TXCLEAR As Integer = &H4
 Private Const GENERIC_READ As Integer = &H80000000
 Private Const GENERIC_WRITE As Integer = &H40000000
 Private Const OPEN_EXISTING As Integer = 3
 Private Const INVALID_HANDLE_VALUE As Integer = -1
 Private Const IO_BUFFER_SIZE As Integer = 1024
 Private Const FILE_FLAG_OVERLAPPED As Int32 = &H40000000
 Private Const ERROR_IO_PENDING As Int32 = 997
 Private Const WAIT_OBJECT_0 As Int32 = 0
 Private Const ERROR_IO_INCOMPLETE As Int32 = 996
 Private Const WAIT_TIMEOUT As Int32 = &H102&
 Private Const INFINITE As Int32 = &HFFFFFFFF


#End Region
#Region "Win32API"
 '// Win32 API
   <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function SetCommState(ByVal hCommDev As IntPtr, ByRef lpDCB As DCB) As Int32
   End Function
   <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function GetCommState(ByVal hCommDev As IntPtr, ByRef lpDCB As DCB) As Int32
   End Function
   <DllImport("kernel32.dll", SetlastError:=True, CharSet:=CharSet.Auto)> Private Shared Function BuildCommDCB(ByVal lpDef As String, ByRef lpDCB As DCB) As Int32
   End Function
   <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function SetupComm(ByVal hFile As IntPtr, ByVal dwInQueue As Int32, ByVal dwOutQueue As Int32) As Int32
   End Function
   <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function SetCommTimeouts(ByVal hFile As IntPtr, ByRef lpCommTimeouts As COMMTIMEOUTS) As Int32
   End Function
   <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function GetCommTimeouts(ByVal hFile As IntPtr, ByRef lpCommTimeouts As COMMTIMEOUTS) As Int32
   End Function
   <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function ClearCommError(ByVal hFile As IntPtr, ByRef lpErrors As Int32, ByRef lpComStat As COMSTAT) As Int32
   End Function
   <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function PurgeComm(ByVal hFile As IntPtr, ByVal dwFlags As Int32) As Int32
   End Function
    <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function EscapeCommFunction(ByVal hFile As IntPtr, ByVal ifunc As Int32) As Boolean
    End Function
    <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function WaitCommEvent(ByVal hFile As IntPtr, ByRef Mask As EventMasks, ByRef lpOverlap As OVERLAPPED) As Int32
    End Function
    <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function WriteFile(ByVal hFile As IntPtr, ByVal Buffer As Byte(), ByVal nNumberOfBytesToWrite As Integer, ByRef lpNumberOfBytesWritten As Integer, ByRef lpOverlapped As OVERLAPPED) As Integer
    End Function
    <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function ReadFile(ByVal hFile As IntPtr, <Out()> ByVal Buffer As Byte(), ByVal nNumberOfBytesToRead As Integer, ByRef lpNumberOfBytesRead As Integer, ByRef lpOverlapped As OVERLAPPED) As Integer
    End Function
    <DllImport("kernel32.dll", SetlastError:=True, CharSet:=CharSet.Auto)> Private Shared Function CreateFile(ByVal lpFileName As String, ByVal dwDesiredAccess As Integer, ByVal dwShareMode As Integer, ByVal lpSecurityAttributes As Integer, ByVal dwCreationDisposition As Integer, ByVal dwFlagsAndAttributes As Integer, ByVal hTemplateFile As Integer) As IntPtr
    End Function
    <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function CloseHandle(ByVal hObject As IntPtr) As Boolean
    End Function
    <DllImport("kernel32.dll", SetlastError:=True)> Public Shared Function GetCommModemStatus(ByVal hFile As IntPtr, ByRef lpModemStatus As Int32) As Boolean
    End Function
    <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function SetEvent(ByVal hEvent As IntPtr) As Boolean
    End Function
    <DllImport("kernel32.dll", SetlastError:=True, CharSet:=CharSet.Auto)> Private Shared Function CreateEvent(ByVal lpEventAttributes As IntPtr, ByVal bManualReset As Int32, ByVal bInitialState As Int32, ByVal lpName As String) As IntPtr
    End Function
    <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function WaitForSingleObject(ByVal hHandle As IntPtr, ByVal dwMilliseconds As Int32) As Int32
    End Function
    <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function GetOverlappedResult(ByVal hFile As IntPtr, ByRef lpOverlapped As OVERLAPPED, ByRef lpNumberOfBytesTransferred As Int32, ByVal bWait As Int32) As Int32
    End Function
    <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function SetCommMask(ByVal hFile As IntPtr, ByVal lpEvtMask As Int32) As Int32
    End Function
    <DllImport("kernel32.dll", SetlastError:=True, CharSet:=CharSet.Auto)> Private Shared Function GetDefaultCommConfig(ByVal lpszName As String, ByRef lpCC As COMMCONFIG, ByRef lpdwSize As Integer) As Boolean
    End Function
    <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function SetCommBreak(ByVal hFile As IntPtr) As Boolean
    End Function
    <DllImport("kernel32.dll", SetlastError:=True)> Private Shared Function ClearCommBreak(ByVal hFile As IntPtr) As Boolean
    End Function


#End Region
#Region "Events"
 Public Event CommEvent As CommEventHandler
#End Region
#Region "Delegates"
 Public Delegate Sub CommEventHandler(ByVal source As Rs232, ByVal Mask As EventMasks)
#End Region

 Public Property Port() As Integer
  '===================================================
  '
  '  Description :  Comunication Port
  '  Created   :  21/09/2001 - 11:25:49
  '
  '            *Parameters Info*
  '
  '  Notes    :
  '===================================================
  Get
   Return miPort
  End Get
  Set(ByVal Value As Integer)
   miPort = Value
  End Set
 End Property
 Public Sub PurgeBuffer(ByVal Mode As PurgeBuffers)
  '===================================================
  '            ?003 ALSTOM FIR S.p.A All rights reserved
  '
  ' Description : Purge Communication Buffer
  ' Created   : 01/09/03 - 10:37:39
  ' Author   : Corrado Cavalli
  '
  '      *Parameters Info*
  '
  ' Notes    : This method will clear any character into buffer, use TxAbort/RxAbort
  '        to terminate any pending overlapped Tx/Rx operation.
  '===================================================
  If (mhRS.ToInt32 > 0) Then PurgeComm(mhRS, Mode)
 End Sub
 Public Overridable Property Timeout() As Integer
  '===================================================
  '
  '  Description:  Comunication timeout in seconds
  '  Created   :  21/09/2001 - 11:26:50
  '
  '            *Parameters Info*
  '
  '  Notes    :
  '===================================================
  Get
   Return miTimeout
  End Get
  Set(ByVal Value As Integer)
   miTimeout = CInt(IIf(Value = 0, 500, Value))
   '// If Port is open updates it on the fly
   pSetTimeout()
  End Set
 End Property
 Public Property Parity() As DataParity
  '===================================================
  '
  '  Description :  Comunication parity
  '  Created   :  21/09/2001 - 11:27:15
  '
  '            *Parameters Info*
  '
  '  Notes    :
  '===================================================
  Get
   Return meParity
  End Get
  Set(ByVal Value As DataParity)
   meParity = Value
  End Set
 End Property
 Public Property StopBit() As DataStopBit
  '===================================================
  '
  '  Description:  Comunication StopBit
  '  Created   :  21/09/2001 - 11:27:37
  '
  '            *Parameters Info*
  '
  '  Notes    :
  '===================================================
  Get
   Return meStopBit
  End Get
  Set(ByVal Value As DataStopBit)
   meStopBit = Value
  End Set
 End Property
 Public Property BaudRate() As Integer
  '===================================================
  '
  '  Description:  Comunication BaudRate
  '  Created   :  21/09/2001 - 11:28:00
  '
  '            *Parameters Info*
  '
  '  Notes    :
  '===================================================
  Get
   Return miBaudRate
  End Get
  Set(ByVal Value As Integer)
   miBaudRate = Value
  End Set
 End Property
 Public Property DataBit() As Integer
  '===================================================
  '
  '  Description :  Comunication DataBit
  '  Created   :  21/09/2001 - 11:28:20
  '
  '            *Parameters Info*
  '
  '  Notes    :
  '===================================================
  Get
   Return miDataBit
  End Get
  Set(ByVal Value As Integer)
   miDataBit = Value
  End Set
 End Property
 Public Property BufferSize() As Integer
  '===================================================
  '
  '  Description :  Receive Buffer size  
  '  Created   :  21/09/2001 - 11:33:05
  '
  '            *Parameters Info*
  '
  '  Notes    :
  '===================================================
  Get
   Return miBufferSize
  End Get
  Set(ByVal Value As Integer)
   miBufferSize = Value
  End Set
 End Property
 Public Overloads Sub Open()
  '===================================================
  '
  '  Description :  Initializes and Opens comunication port
  '  Created   :  21/09/2001 - 11:33:40
  '
  '            *Parameters Info*
  '
  '  Notes    :
  '===================================================
  '// Get Dcb block,Update with current data
  Dim uDcb As DCB, iRc As Int32
  '// Set working mode
  meMode = Mode.Overlapped
  Dim iMode As Int32 = Convert.ToInt32(IIf(meMode = Mode.Overlapped, FILE_FLAG_OVERLAPPED, 0))
  '// Initializes Com Port
  If miPort > 0 Then
   Try
    '// Creates a COM Port stream handle
    mhRS = CreateFile("\\.\COM" & miPort.ToString, GENERIC_READ Or GENERIC_WRITE, 0, 0, OPEN_EXISTING, iMode, 0)
    If (mhRS.ToInt32 > 0) Then
     '// Clear all comunication errors
     Dim lpErrCode As Int32
     iRc = ClearCommError(mhRS, lpErrCode, New COMSTAT)
     '// Clears I/O buffers
     iRc = PurgeComm(mhRS, PurgeBuffers.RXClear Or PurgeBuffers.TxClear)
     '// Gets COM Settings
     iRc = GetCommState(mhRS, uDcb)
     '// Updates COM Settings
     Dim sParity As String = "NOEM"
     sParity = sParity.Substring(meParity, 1)
     '// Set DCB State
     Dim sDCBState As String = String.Format("baud={0} parity={1} data={2} stop={3}", miBaudRate, sParity, miDataBit, CInt(meStopBit))
     iRc = BuildCommDCB(sDCBState, uDcb)
     uDcb.Parity = CByte(meParity)
     '// Set Xon/Xoff State
     If mbUseXonXoff Then
      uDcb.Bits1 = 768
     Else
      uDcb.Bits1 = 0
     End If
     iRc = SetCommState(mhRS, uDcb)
     If iRc = 0 Then
      Dim sErrTxt As String = New Win32Exception().Message
      Throw New CIOChannelException("Unable to set COM state " & sErrTxt)
     End If
     '// Setup Buffers (Rx,Tx)
     iRc = SetupComm(mhRS, miBufferSize, miBufferSize)
     '// Set Timeouts
     pSetTimeout()
     '//Enables events if required
     If mbEnableEvents Then Me.EnableEvents()
    Else
     '// Raise Initialization problems
     Dim sErrTxt As String = New Win32Exception().Message
     Throw New CIOChannelException("Unable to open COM" + miPort.ToString + ControlChars.CrLf + sErrTxt)
    End If
   Catch Ex As Exception
    '// Generica error
    Throw New CIOChannelException(Ex.Message, Ex)
   End Try
  Else
   '// Port not defined, cannot open
   Throw New ApplicationException("COM Port not defined,use Port property to set it before invoking InitPort")
  End If
 End Sub
 Public Overloads Sub Open(ByVal Port As Integer, ByVal BaudRate As Integer, ByVal DataBit As Integer, ByVal Parity As DataParity, ByVal StopBit As DataStopBit, ByVal BufferSize As Integer)
  '===================================================
  '
  '  Description:  Opens comunication port (Overloaded method)
  '  Created  :  21/09/2001 - 11:33:40
  '
  '            *Parameters Info*
  '
  '  Notes   :
  '===================================================
  Me.Port = Port
  Me.BaudRate = BaudRate
  Me.DataBit = DataBit
  Me.Parity = Parity
  Me.StopBit = StopBit
  Me.BufferSize = BufferSize
  Open()
 End Sub
 Public Sub Close()
  '===================================================
  '
  '  Description:  Close comunication channel
  '  Created   :  21/09/2001 - 11:38:00
  '
  '            *Parameters Info*
  '
  '  Notes    :
  '===================================================
  If mhRS.ToInt32 > 0 Then
   If mbEnableEvents = True Then
    Me.DisableEvents()
   End If
   Dim ret As Boolean = CloseHandle(mhRS)
   If Not ret Then Throw New Win32Exception
   mhRS = New IntPtr(0)
  End If
 End Sub
 ReadOnly Property IsOpen() As Boolean
  '===================================================
  '
  '  Description:  Returns Port Status  
  '  Created   :  21/09/2001 - 11:38:51
  '
  '            *Parameters Info*
  '
  '  Notes    :
  '===================================================
  Get
   Return CBool(mhRS.ToInt32 > 0)
  End Get
 End Property
 Public Overloads Sub Write(ByVal Buffer As Byte())
  '===================================================
  '
  '  Description:  Transmit a stream
  '  Created   :  21/09/2001 - 11:39:51
  '
  '            *Parameters Info*
  '  Buffer    :   Array of Byte() to write
  '  Notes    :
  '===================================================
  Dim iRc, iBytesWritten As Integer, hOvl As GCHandle
  '-----------------------------------------------------------------
  muOvlW = New Overlapped
  If mhRS.ToInt32 <= 0 Then
   Throw New ApplicationException("Please initialize and open port before using this method")
  Else
   '// Creates Event
   Try
                hOvl = GCHandle.Alloc(muOvlW, GCHandleType.Pinned)
    muOvlW.hEvent = CreateEvent(Nothing, 1, 0, Nothing)
    If muOvlW.hEvent.ToInt32 = 0 Then Throw New ApplicationException("Error creating event for overlapped writing")
    '// Clears IO buffers and sends data
    iRc = WriteFile(mhRS, Buffer, Buffer.Length, 0, muOvlW)
    If iRc = 0 Then
     If Marshal.GetLastWin32Error <> ERROR_IO_PENDING Then
      Throw New ApplicationException("Write command error")
     Else
      '// Check Tx results
      If GetOverlappedResult(mhRS, muOvlW, iBytesWritten, 1) = 0 Then
       Throw New ApplicationException("Write pending error")
      Else
       '// All bytes sent?
       If iBytesWritten <> Buffer.Length Then Throw New ApplicationException("Write Error - Bytes Written " & iBytesWritten.ToString & " of " & Buffer.Length.ToString)
      End If
     End If
    End If
   Finally
    '//Closes handle
    CloseHandle(muOvlW.hEvent)
                If (hOvl.IsAllocated = True) Then hOvl.Free()
   End Try
  End If
 End Sub
 Public Overloads Sub Write(ByVal Buffer As String)
  '===================================================
  '
  ' Description : Writes a string to RS232
  ' Created   : 04/02/2002 - 8:46:42
  '
  '      *Parameters Info*
  '
  ' Notes    :  24/05/2002 Fixed problem with ASCII Encoding
  '===================================================
  Dim oEncoder As New System.Text.ASCIIEncoding
  Dim oEnc As Encoding = oEncoder.GetEncoding(1252)
  '-------------------------------------------------------------
  Dim aByte() As Byte = oEnc.GetBytes(Buffer)
  Me.Write(aByte)
 End Sub
 Public Function Read(ByVal Bytes2Read As Integer) As Integer
  '===================================================
  '
  '  Description:  Read Bytes from Port
  '  Created   :  21/09/2001 - 11:41:17
  '
  '            *Parameters Info*
  '  Bytes2Read  :  Bytes to read from port
  '  Returns     :  Number of readed chars
  '
  '  Notes    :
  '===================================================
  Dim iReadChars, iRc As Integer, bReading As Boolean, hOvl As GCHandle
  '--------------------------------------------------------------
  '// If Bytes2Read not specified uses Buffersize
  If Bytes2Read = 0 Then Bytes2Read = miBufferSize
  muOvlR = New Overlapped
  If mhRS.ToInt32 <= 0 Then
   Throw New ApplicationException("Please initialize and open port before using this method")
  Else
   '// Get bytes from port
   Try
                hOvl = GCHandle.Alloc(muOvlR, GCHandleType.Pinned)
    muOvlR.hEvent = CreateEvent(Nothing, 1, 0, Nothing)
    If muOvlR.hEvent.ToInt32 = 0 Then Throw New ApplicationException("Error creating event for overlapped reading")
    '// Clears IO buffers and reads data
    ReDim mabtRxBuf(Bytes2Read - 1)
    iRc = ReadFile(mhRS, mabtRxBuf, Bytes2Read, iReadChars, muOvlR)
    If iRc = 0 Then
     If Marshal.GetLastWin32Error() <> ERROR_IO_PENDING Then
      Throw New ApplicationException("Read pending error")
     Else
      '// Wait for characters
      iRc = WaitForSingleObject(muOvlR.hEvent, miTimeout)
      Select Case iRc
       Case WAIT_OBJECT_0
        '// Some data received...
        If GetOverlappedResult(mhRS, muOvlR, iReadChars, 0) = 0 Then
         Throw New ApplicationException("Read pending error.")
        Else
         Return iReadChars
        End If
       Case WAIT_TIMEOUT
        Throw New IOTimeoutException("Read Timeout.")
       Case Else
        Throw New ApplicationException("General read error.")
      End Select
     End If
    Else
     Return (iReadChars)
    End If
   Finally
    '//Closes handle
    CloseHandle(muOvlR.hEvent)
    If (hOvl.IsAllocated) Then hOvl.Free()
   End Try
  End If
 End Function
 Overridable ReadOnly Property InputStream() As Byte()
  '===================================================
  '
  '  Description:  Returns received data as Byte() 
  '  Created   :  21/09/2001 - 11:45:06
  '
  '            *Parameters Info*
  '  
  '  Notes    :
  '===================================================
      Get
         Return mabtRxBuf
      End Get
   End Property
 Overridable ReadOnly Property InputStreamString() As String
  '===================================================
  '
  ' Description : Return a string containing received data
  ' Created   : 04/02/2002 - 8:49:55
  '
  '      *Parameters Info*
  '
  ' Notes    :
  '===================================================
  Get
         Dim oEncoder As New System.Text.ASCIIEncoding
         Dim oEnc As Encoding = oEncoder.GetEncoding(1252)
   '-------------------------------------------------------------
   If Not Me.InputStream Is Nothing Then Return oEnc.GetString(Me.InputStream)
  End Get
 End Property
 Public Sub ClearInputBuffer()
  '===================================================
  '
  '  Description:  Clears Input buffer
  '  Created   :  21/09/2001 - 11:45:34
  '
  '            *Parameters Info*
  '
  '  Notes    :  Gets all character until end of buffer
  '===================================================
  If mhRS.ToInt32 > 0 Then
   PurgeComm(mhRS, PURGE_RXCLEAR)
  End If
 End Sub
 Public WriteOnly Property Rts() As Boolean
  '===================================================
  '
  '  Description:  Set/Resets RTS Line  
  '  Created   :  21/09/2001 - 11:45:34
  '
  '            *Parameters Info*
  '
  '  Notes    :
  '===================================================
  Set(ByVal Value As Boolean)
   If mhRS.ToInt32 > 0 Then
    If Value Then
     EscapeCommFunction(mhRS, Lines.SetRts)
    Else
     EscapeCommFunction(mhRS, Lines.ClearRts)
    End If
   End If
  End Set
 End Property
 Public WriteOnly Property Dtr() As Boolean
  '===================================================
  '
  '  Description:  Set/Resets DTR Line  
  '  Created   :  21/09/2001 - 11:45:34
  '
  '            *Parameters Info*
  '
  '  Notes    :
  '===================================================
  Set(ByVal Value As Boolean)
   If mhRS.ToInt32 > 0 Then
    If Value Then
     EscapeCommFunction(mhRS, Lines.SetDtr)
    Else
     EscapeCommFunction(mhRS, Lines.ClearDtr)
    End If
   End If
  End Set
 End Property
 Public ReadOnly Property ModemStatus() As ModemStatusBits
  '===================================================
  '
  ' Description : Gets Modem status
  ' Created   : 28/02/2002 - 8:58:04
  '
  '      *Parameters Info*
  '
  ' Notes    :
  '===================================================
  Get
   If mhRS.ToInt32 <= 0 Then
    Throw New ApplicationException("Please initialize and open port before using this method")
   Else
    '// Retrieve modem status
    Dim lpModemStatus As Int32
    If Not GetCommModemStatus(mhRS, lpModemStatus) Then
     Throw New ApplicationException("Unable to get modem status")
    Else
     Return CType(lpModemStatus, ModemStatusBits)
    End If
   End If
  End Get
 End Property
 Public Function CheckLineStatus(ByVal Line As ModemStatusBits) As Boolean
  '===================================================
  '
  ' Description : Check status of a Modem Line
  ' Created   : 28/02/2002 - 10:25:17
  '
  '      *Parameters Info*
  '
  ' Notes    :
  '===================================================
  Return Convert.ToBoolean(ModemStatus And Line)
 End Function
 Public Property UseXonXoff() As Boolean
  '===================================================
  '
  ' Description : Set XON/XOFF mode
  ' Created   : 26/05/2003 - 21:16:18
  '
  '      *Parameters Info*
  '
  ' Notes    :
  '===================================================
  Get
   Return mbUseXonXoff
  End Get
  Set(ByVal Value As Boolean)
   mbUseXonXoff = Value
  End Set
 End Property
 Public Sub EnableEvents()
  '===================================================
  '
  ' Description : Enables monitoring of incoming events
  ' Created   : 15/07/2003 - 12:00:56
  '
  '      *Parameters Info*
  '
  ' Notes    :
  '===================================================
  If mhRS.ToInt32 <= 0 Then
   Throw New ApplicationException("Please initialize and open port before using this method")
  Else
   If moEvents Is Nothing Then
    mbEnableEvents = True
    moEvents = New Thread(AddressOf pEventsWatcher)
    moEvents.IsBackground = True
    moEvents.Start()
   End If
  End If
 End Sub
 Public Sub DisableEvents()
  '===================================================
  '
  ' Description : Disables monitoring of incoming events
  ' Created   : 15/07/2003 - 12:00:56
  '
  '      *Parameters Info*
  '
  ' Notes    :
  '===================================================
  If mbEnableEvents = True Then
   SyncLock Me
    mbEnableEvents = False     '// This should kill the thread
   End SyncLock
   '// Let WaitCommEvent exit...
   If muOvlE.hEvent.ToInt32 <> 0 Then SetEvent(muOvlE.hEvent)
   moEvents = Nothing
  End If
 End Sub
 Public Property RxBufferThreshold() As Int32
  '===================================================
  '        '
  ' Description : Numer of characters into input buffer
  ' Created   : 16/07/03 - 9:00:57
  ' Author   : Corrado Cavalli
  '
  '      *Parameters Info*
  '
  ' Notes    :
  '===================================================
  Get
   Return miBufThreshold
  End Get
  Set(ByVal Value As Int32)
   miBufThreshold = Value
  End Set
 End Property
    Public Shared Function IsPortAvailable(ByVal portNumber As Int32) As Boolean
        '===================================================
        '                '
        ' Description : Returns true if a specific port number is supported by the system
        ' Created   : 14/09/03 - 17:00:57
        ' Author   : Corrado Cavalli
        '
        '      *Parameters Info*
        ' portNumber : port number to check
        '
        ' Notes    :
        '===================================================
        If portNumber <= 0 Then
            Return False
        Else
            Dim cfg As COMMCONFIG
            Dim cfgsize As Int32 = Marshal.SizeOf(cfg)
            cfg.dwSize = cfgsize
            Dim ret As Boolean = GetDefaultCommConfig("COM" + portNumber.ToString, cfg, cfgsize)
            Return ret
        End If
    End Function
    Public Sub SetBreak()
        '===================================================
        '                '
        ' Description : Set COM in break modem
        ' Created   : 12/10/03 - 10:00:57
        ' Author   : Corrado Cavalli
        '
        '      *Parameters Info*
        ' 
        '
        ' Notes    :
        '===================================================
        If mhRS.ToInt32 > 0 Then
            If SetCommBreak(mhRS) = False Then Throw New Win32Exception
        End If
    End Sub
    Public Sub ClearBreak()
        '===================================================
        '              '
        ' Description : Clear COM break mode
        ' Created   : 12/10/03 - 10:02:57
        ' Author   : Corrado Cavalli
        '
        '      *Parameters Info*
        ' 
        '
        ' Notes    :
        '===================================================
        If mhRS.ToInt32 > 0 Then
            If ClearCommBreak(mhRS) = False Then Throw New Win32Exception
        End If

    End Sub
    Public ReadOnly Property InBufferCount() As Int32
        '===================================================
        '               '
        ' Description : Returns the number of bytes inside Rx buffer
        ' Created   : 20/04/05 - 10:02:57
        ' Author   : Corrado Cavalli/Jean-Pierre ZANIER
        '
        '
        '===================================================
        Get
            Dim comStat As COMSTAT
            Dim lpErrCode As Int32
            Dim iRc As Int32
            comStat.cbInQue = 0
            If mhRS.ToInt32 > 0 Then
                iRc = ClearCommError(mhRS, lpErrCode, comStat)
                Return comStat.cbInQue
            End If
            Return 0
        End Get
    End Property


#Region "Finalize"
    Protected Overrides Sub Finalize()
        '===================================================
        '
        ' Description : Closes COM port if object is garbage collected and still owns
        '                       COM port reosurces
        '
        ' Created   : 27/05/2002 - 19:05:56
        '
        '      *Parameters Info*
        '
        ' Notes    :
        '===================================================
        Try
            If Not mbDisposed Then
                If mbEnableEvents Then Me.DisableEvents()
                Close()
            End If
        Finally
            MyBase.Finalize()
        End Try
    End Sub
#End Region

#Region "Private Routines"
    Private Sub pSetTimeout()
        '===================================================
        '
        '  Description:  Set comunication timeouts
        '  Created   :  21/09/2001 - 11:46:40
        '
        '            *Parameters Info*
        '
        '  Notes    :
        '===================================================
        Dim uCtm As COMMTIMEOUTS
        '// Set ComTimeout
        If mhRS.ToInt32 <= 0 Then
            Exit Sub
        Else
            '// Changes setup on the fly
            With uCtm
                .ReadIntervalTimeout = 0
                .ReadTotalTimeoutMultiplier = 0
                .ReadTotalTimeoutConstant = miTimeout
                .WriteTotalTimeoutMultiplier = 10
                .WriteTotalTimeoutConstant = 100
            End With
            SetCommTimeouts(mhRS, uCtm)
        End If
    End Sub
    Private Sub pDispose() Implements IDisposable.Dispose
        '===================================================
        '
        ' Description : Handles correct class disposing Write
        ' Created   : 27/05/2002 - 19:03:06
        '
        '      *Parameters Info*
        '
        ' Notes    :
        '===================================================
        If (Not mbDisposed AndAlso (mhRS.ToInt32 > 0)) Then
            '// Closes Com Port releasing resources
            Try
                Me.Close()
            Finally
                mbDisposed = True
                '// Suppress unnecessary Finalize overhead
                GC.SuppressFinalize(Me)
            End Try
        End If


    End Sub
    Private Sub pEventsWatcher()
        '===================================================
        '               '
        ' Description : Watches for all events raising events when they arrive to the port
        ' Created   : 15/07/03 - 11:45:13
        ' Author   : Corrado Cavalli
        '
        '      *Parameters Info*
        '
        ' Notes    :
        '===================================================
        '// Events to watch
        Dim lMask As EventMasks = EventMasks.Break Or EventMasks.CarrierDetect Or EventMasks.ClearToSend Or _
        EventMasks.DataSetReady Or EventMasks.Ring Or EventMasks.RxChar Or EventMasks.RXFlag Or _
        EventMasks.StatusError
        Dim lRetMask As EventMasks, iBytesRead, iTotBytes, iErrMask As Int32, iRc As Int32, aBuf As New ArrayList
        Dim uComStat As COMSTAT
        '-----------------------------------
        '// Creates Event
        muOvlE = New Overlapped
        Dim hOvlE As GCHandle = GCHandle.Alloc(muOvlE, GCHandleType.Pinned)
        muOvlE.hEvent = CreateEvent(Nothing, 1, 0, Nothing)
        If muOvlE.hEvent.ToInt32 = 0 Then Throw New ApplicationException("Error creating event for overlapped reading")
        '// Set mask
        SetCommMask(mhRS, lMask)
        '// Looks for RxChar
        While mbEnableEvents = True
            WaitCommEvent(mhRS, lMask, muOvlE)
            Select Case WaitForSingleObject(muOvlE.hEvent, INFINITE)
                Case WAIT_OBJECT_0
                    '// Event (or abort) detected
                    If mbEnableEvents = False Then Exit While
                    If (lMask And EventMasks.RxChar) > 0 Then
                        '// Read incoming data
                        ClearCommError(mhRS, iErrMask, uComStat)
                        If iErrMask = 0 Then
                            Dim ovl As New Overlapped
                            Dim hOvl As GCHandle = GCHandle.Alloc(ovl, GCHandleType.Pinned)
                            ReDim mabtRxBuf(uComStat.cbInQue - 1)
                            If ReadFile(mhRS, mabtRxBuf, uComStat.cbInQue, iBytesRead, ovl) > 0 Then
                                If iBytesRead > 0 Then
                                    '// Some bytes read, fills temporary buffer
                                    If iTotBytes < miBufThreshold Then
                                        aBuf.AddRange(mabtRxBuf)
                                        iTotBytes += iBytesRead
                                    End If
                                    '// Threshold reached?, raises event
                                    If iTotBytes >= miBufThreshold Then
                                        '//Copies temp buffer into Rx buffer
                                        ReDim mabtRxBuf(iTotBytes - 1)
                                        aBuf.CopyTo(mabtRxBuf)
                                        '// Raises event
                                        Try
                                            Me.OnCommEventReceived(Me, lMask)
                                        Finally
                                            iTotBytes = 0
                                            aBuf.Clear()
                                        End Try
                                    End If
                                End If
                            End If
                            If (hOvl.IsAllocated) Then hOvl.Free()
                        End If
                    Else
                        '// Simply raises OnCommEventHandler event
                        Me.OnCommEventReceived(Me, lMask)
                    End If
                Case Else
                    Dim sErr As String = New Win32Exception().Message
                    Throw New ApplicationException(sErr)
            End Select
        End While
        '// Release Event Handle
        CloseHandle(muOvlE.hEvent)
        muOvlE.hEvent = IntPtr.Zero
        If (hOvlE.IsAllocated) Then hOvlE.Free()
        muOvlE = Nothing
    End Sub

 

#End Region

#Region "Protected Routines"
    Protected Sub OnCommEventReceived(ByVal source As Rs232, ByVal mask As EventMasks)
        '===================================================
        '             '
        ' Description : Raises CommEvent
        ' Created   : 15/07/03 - 15:09:50
        ' Author   : Corrado Cavalli
        '
        '      *Parameters Info*
        '
        ' Notes    :
        '===================================================
        Dim del As CommEventHandler = Me.CommEventEvent
        If (Not del Is Nothing) Then
            Dim SafeInvoker As ISynchronizeInvoke
            Try
                SafeInvoker = DirectCast(del.Target, ISynchronizeInvoke)
            Catch
            End Try
            If (Not SafeInvoker Is Nothing) Then
                SafeInvoker.Invoke(del, New Object() {source, mask})
            Else
                del.Invoke(source, mask)
            End If
        End If
    End Sub
#End Region

End Class
#End Region

#Region "Exceptions"
Public Class CIOChannelException : Inherits ApplicationException
 '===================================================
 '
 '  Module   :  CChannellException
 '  Description:  Customized Channell Exception
 '  Created   :  17/10/2001 - 10:32:37
 '
 '  Notes    :  This exception is raised when NACK error found
 '===================================================
 Sub New(ByVal Message As String)
  MyBase.New(Message)
 End Sub
 Sub New(ByVal Message As String, ByVal InnerException As Exception)
  MyBase.New(Message, InnerException)
 End Sub
End Class
Public Class IOTimeoutException : Inherits CIOChannelException
 '===================================================
 '
 ' Description : Timeout customized exception
 ' Created   : 28/02/2002 - 10:43:43
 '
 '      *Parameters Info*
 '
 ' Notes    :
 '===================================================
 Sub New(ByVal Message As String)
  MyBase.New(Message)
 End Sub
 Sub New(ByVal Message As String, ByVal InnerException As Exception)
  MyBase.New(Message, InnerException)
 End Sub
End Class

#End Region

 

轉載於:https://www.cnblogs.com/msnadair/archive/2007/05/14/745993.html

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