rs232.txt

VS2005

' 版权所有 (C) Microsoft Corporation。保留所有权利。
Imports System.Runtime.InteropServices
Imports System.Text
Imports System.Threading

Public Class RS232

    ' 声明必需的类变量及其初始值。
    Private mhRS As Integer = -1   ' Com 端口的句柄
    Private miPort As Integer = 1   ' 默认值为 COM1
    Private miTimeout As Integer = 70   ' 超时设置，以 ms 为单位
    Private miBaudRate As Integer = 9600
    Private meParity As DataParity = 0
    Private meStopBit As DataStopBit = 0
    Private miDataBit As Integer = 8
    Private miBufferSize As Integer = 512   ' 缓冲区大小默认值为 512 字节
    Private mabtRxBuf As Byte()   ' 接收缓冲区
    Private meMode As Mode  ' 类工作模式
    Private mbWaitOnRead As Boolean
    Private mbWaitOnWrite As Boolean
    Private mbWriteErr As Boolean
    Private muOverlapped As OVERLAPPED
    Private muOverlappedW As OVERLAPPED
    Private muOverlappedE As OVERLAPPED
    Private mabtTmpTxBuf As Byte()  ' Async Tx 使用的临时缓冲区
    Private moThreadTx As Thread
    Private moThreadRx As Thread
    Private miTmpBytes2Read As Integer
    Private meMask As EventMasks

#Region "枚举"

    ' 此枚举提供数据奇偶校验值。
    Public Enum DataParity
        Parity_None = 0
        Pariti_Odd
        Parity_Even
        Parity_Mark
    End Enum

    ' 此枚举提供数据停止位数值。
    ' 它被设置为从一开始，因此枚举值
    ' 与实际值匹配。
    Public Enum DataStopBit
        StopBit_1 = 1
        StopBit_2
    End Enum

    ' 此枚举包含用于清除各缓冲区的值。
    Private Enum PurgeBuffers
        RXAbort = &H2
        RXClear = &H8
        TxAbort = &H1
        TxClear = &H4
    End Enum

    ' 此枚举为发送到 Comm 端口的行提供值
    Private Enum Lines
        SetRts = 3
        ClearRts = 4
        SetDtr = 5
        ClearDtr = 6
        ResetDev = 7   ' 可能时重置设备
        SetBreak = 8   ' 设置设备分行符。
        ClearBreak = 9   ' 清除设备分行符。
    End Enum
    ' 此枚举为调制解调器状态提供值，因为
    ' 我们将主要与调制解调器进行通信。
    ' 注意，Flags() 属性设置为允许对值进行
    ' 按位组合。
    <Flags()> Public Enum ModemStatusBits
        ClearToSendOn = &H10
        DataSetReadyOn = &H20
        RingIndicatorOn = &H40
        CarrierDetect = &H80
    End Enum

    ' 此枚举为工作模式提供值
    Public Enum Mode
        NonOverlapped
        Overlapped
    End Enum

    ' 此枚举为使用的 Comm 掩码提供值。
    ' 注意，Flags() 属性设置为允许对值进行
    ' 按位组合。
    <Flags()> Public Enum EventMasks
        RxChar = &H1
        RXFlag = &H2
        TxBufferEmpty = &H4
        ClearToSend = &H8
        DataSetReady = &H10
        ReceiveLine = &H20
        Break = &H40
        StatusError = &H80
        Ring = &H100
    End Enum
#End Region

#Region "结构"
    ' 这是对 Windows API 的调用使用的 DCB 结构。
    <StructLayout(LayoutKind.Sequential, Pack:=1)> Private Structure DCB
        Public DCBlength As Integer
        Public BaudRate As Integer
        Public Bits1 As Integer
        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 Byte
        Public XoffChar As Byte
        Public ErrorChar As Byte
        Public EofChar As Byte
        Public EvtChar As Byte
        Public wReserved2 As Int16
    End Structure

    ' 这是对 Windows API 的调用使用的 CommTimeOuts 结构。
    <StructLayout(LayoutKind.Sequential, Pack:=1)> Private Structure COMMTIMEOUTS
        Public ReadIntervalTimeout As Integer
        Public ReadTotalTimeoutMultiplier As Integer
        Public ReadTotalTimeoutConstant As Integer
        Public WriteTotalTimeoutMultiplier As Integer
        Public WriteTotalTimeoutConstant As Integer
    End Structure

    ' 这是对 Windows API 的调用使用的 CommConfig 结构。
    <StructLayout(LayoutKind.Sequential, Pack:=1)> Private Structure COMMCONFIG
        Public dwSize As Integer
        Public wVersion As Int16
        Public wReserved As Int16
        Public dcbx As DCB
        Public dwProviderSubType As Integer
        Public dwProviderOffset As Integer
        Public dwProviderSize As Integer
        Public wcProviderData As Byte
    End Structure

    ' 这是对 Windows API 的调用使用的 OverLapped 结构。
    <StructLayout(LayoutKind.Sequential, Pack:=1)> Public Structure OVERLAPPED
        Public Internal As Integer
        Public InternalHigh As Integer
        Public Offset As Integer
        Public OffsetHigh As Integer
        Public hEvent As Integer
    End Structure
#End Region

#Region "异常"

    ' 此类定义一个自定义信道异常。此异常在
    ' 引发 NACK 时引发。
    Public Class CIOChannelException : Inherits ApplicationException
        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

    ' 此类定义一个自定义超时异常。
    Public Class IOTimeoutException : Inherits CIOChannelException
        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

#Region "事件"
    ' 此事件允许程序使用此类对 Comm 端口事件
    ' 做出响应。
    Public Event DataReceived(ByVal Source As RS232, ByVal DataBuffer() As Byte)
    Public Event TxCompleted(ByVal Source As RS232)
    Public Event CommEvent(ByVal Source As RS232, ByVal Mask As EventMasks)
#End Region

#Region "常量"
    ' 这些常量用于使代码更清楚。
    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 Integer = &H40000000
    Private Const ERROR_IO_PENDING As Integer = 997
    Private Const WAIT_OBJECT_0 As Integer = 0
    Private Const ERROR_IO_INCOMPLETE As Integer = 996
    Private Const WAIT_TIMEOUT As Integer = &H102&
    Private Const INFINITE As Integer = &HFFFFFFFF


#End Region

#Region "属性"

    ' 此属性获取或设置 BaudRate
    Public Property BaudRate() As Integer
        Get
            Return miBaudRate
        End Get
        Set(ByVal Value As Integer)
            miBaudRate = Value
        End Set
    End Property

    ' 此属性获取或设置 BufferSize
    Public Property BufferSize() As Integer
        Get
            Return miBufferSize
        End Get
        Set(ByVal Value As Integer)
            miBufferSize = Value
        End Set
    End Property

    ' 此属性获取或设置 DataBit。
    Public Property DataBit() As Integer
        Get
            Return miDataBit
        End Get
        Set(ByVal Value As Integer)
            miDataBit = Value
        End Set
    End Property

    ' 此只写属性获取或重置 DTR 行。
    Public WriteOnly Property Dtr() As Boolean
        Set(ByVal Value As Boolean)
            If Not mhRS = -1 Then
                If Value Then
                    EscapeCommFunction(mhRS, Lines.SetDtr)
                Else
                    EscapeCommFunction(mhRS, Lines.ClearDtr)
                End If
            End If
        End Set
    End Property

    ' 此只读属性返回表示进入 Comm 端口的输入的
    ' 字节数组。
    Overridable ReadOnly Property InputStream() As Byte()
        Get
            Return mabtRxBuf
        End Get
    End Property

    ' 此只读属性返回表示进入 Comm 端口的数据的
    ' 字符串。
    Overridable ReadOnly Property InputStreamString() As String
        Get
            Dim oEncoder As New System.Text.ASCIIEncoding()
            Return oEncoder.GetString(Me.InputStream)
        End Get
    End Property

    ' 此属性返回 Comm 端口的打开状态。
    ReadOnly Property IsOpen() As Boolean
        Get
            Return CBool(mhRS <> -1)
        End Get
    End Property

    ' 此只读属性返回调制解调器的状态。
    Public ReadOnly Property ModemStatus() As ModemStatusBits
        Get
            If mhRS = -1 Then
                Throw New ApplicationException("Please initialize and open " + _
                    "port before using this method")
            Else
                ' 检索调制解调器状态
                Dim lpModemStatus As Integer
                If Not GetCommModemStatus(mhRS, lpModemStatus) Then