comm.vb

用VB.NET2003编写的基于WINDOWS API 函数的PDA串行通讯子程序库

        ByRef lpOverlapped As OVERLAPPED) As Integer
    End Function

#End Region
#Region "Properties"
    Overridable ReadOnly Property InputStream() As Byte()
        Get
            Return mbytRxBuffer
        End Get
    End Property
    Public Property Port() As Integer
        Get
            Return miPort
        End Get
        Set(ByVal Value As Integer)
            miPort = Value
        End Set
    End Property

    Public Property DataBit() As Integer
        Get
            Return miDataBit
        End Get
        Set(ByVal Value As Integer)
            miDataBit = Value
        End Set
    End Property
    Public Property StopBit() As DataStopBit
        Get
            Return meStopBit
        End Get
        Set(ByVal Value As DataStopBit)
            meStopBit = Value
        End Set
    End Property
    Public Property BufferSize() As Integer
        Get
            Return miBufferSize
        End Get
        Set(ByVal Value As Integer)
            miBufferSize = Value
        End Set
    End Property



    Public Property BaudRate() As Integer
        Get
            Return mintBaudRate
        End Get
        Set(ByVal Value As Integer)
            mintBaudRate = Value
        End Set
    End Property
    Public ReadOnly Property CommID() As Integer
        Get
            Return mintHandle
        End Get
    End Property

    Public Property CommPort() As Integer
        Get
            Return mintPort

        End Get
        Set(ByVal Value As Integer)
            mintPort = Value
            If ((mintPort < 1) Or (mintPort > 16)) Then
                Throw New Exception("Invalid port number")
            Else
                ' try to open the port to see if it's available.
                mintHandle = CreateFile("COM" + mintPort.ToString() + ":", GENERIC_READ Or GENERIC_WRITE, 0, 0, OPEN_EXISTING, 0, 0)
                If (mintHandle = INVALID_HANDLE_VALUE) Then
                    Throw New Exception("Port is already in use.")
                Else
                    mintHandle = Close(mintHandle)
                End If
            End If
        End Set
    End Property

    Public Property DataBits() As Integer
        Get
            Dim retval As Integer = 0
            Select Case mbytDataBits
                Case DATABITS_5
                    retval = 5
                Case DATABITS_6
                    retval = 6
                Case DATABITS_7
                    retval = 7
                Case DATABITS_8
                    retval = 8
            End Select
            Return retval
        End Get
        Set(ByVal Value As Integer)
            Select Case Value
                Case 5
                    mbytDataBits = DATABITS_5
                Case 6
                    mbytDataBits = DATABITS_6
                Case 7
                    mbytDataBits = DATABITS_7
                Case 8
                    mbytDataBits = DATABITS_8
                Case Else
                    Throw New Exception("Invalid number of data bits.")
            End Select
        End Set
    End Property

    Public Property InputLen() As Integer
        Get
            Return mintRXBufferSize
        End Get
        Set(ByVal Value As Integer)
            mintRXBufferSize = Value
        End Set
    End Property

    Public Property OutputLen() As Integer
        Get
            Return mintTXBufferSize
        End Get
        Set(ByVal Value As Integer)
            mintTXBufferSize = Value
        End Set
    End Property

    Public Property Parity() As String
        Get
            Dim retval As String = ""
            Select Case mbytParity
                Case EVENPARITY
                    retval = "E"
                Case MARKPARITY
                    retval = "M"
                Case NOPARITY
                    retval = "N"
                Case ODDPARITY
                    retval = "O"
                Case SPACEPARITY
                    retval = "S"
            End Select
            Return retval
        End Get
        Set(ByVal Value As String)
            If (Value.Length > 1) Then
                Value = Value.Substring(0, 1)
                Select Case Value
                    Case "E"
                        mbytParity = EVENPARITY
                    Case "M"
                        mbytParity = MARKPARITY
                    Case "N"
                        mbytParity = NOPARITY
                    Case "O"
                        mbytParity = ODDPARITY
                    Case "S"
                        mbytParity = SPACEPARITY
                    Case Else
                        Throw New Exception("Invalid parity attribute.")
                End Select
            End If
        End Set
    End Property

    Public Property StopBits() As Integer

        Get
            Dim retval As Integer = 0
            Select Case mbytStopBits
                Case STOPBITS_10
                    retval = 1
                Case STOPBITS_15
                    retval = 2
                Case STOPBITS_20
                    retval = 3
            End Select
            Return retval
        End Get
        Set(ByVal Value As Integer)
            Select Case Value
                Case 1
                    mbytStopBits = STOPBITS_10
                Case 2
                    mbytStopBits = STOPBITS_15
                Case 3
                    mbytStopBits = STOPBITS_20
                Case Else
                    Throw New Exception("Invalid number of stop bits.")
            End Select
        End Set
    End Property

    Public Property Timeout() As Integer
        Get
            Return mintTimeout
        End Get
        Set(ByVal Value As Integer)
            mintTimeout = Value
        End Set
    End Property
#End Region
#Region "通讯子程序"
    ' This function returns an integer specifying the number of bytes 
    '   read from the Comm Port. It accepts a parameter specifying the number
    '   of desired bytes to read.
    Public Function Read(ByVal mhRS As Integer, ByVal Bytes2Read As Integer) As Integer
        Dim iReadChars, iRc As Integer

        ' If Bytes2Read not specified uses Buffersize
        If Bytes2Read = 0 Then Bytes2Read = 512
        If mhRS = -1 Then
            Throw New ApplicationException( _
                "Please initialize and open port before using this method")
        Else
            ' Get bytes from port
            Try

                ' Purge buffers
                'PurgeComm(mhRS, PURGE_RXCLEAR Or PURGE_TXCLEAR)
                ' Creates an event for overlapped operations
                ' Non overlapped mode
                ReDim mbytRxBuffer(Bytes2Read - 1)
                iRc = ReadFile(mhRS, mbytRxBuffer, Bytes2Read, iReadChars, Nothing)
                If iRc = 0 Then
                    ' Read Error
                    Throw New ApplicationException( _
                        "ReadFile error " & iRc.ToString)
                Else
                    ' Handles timeout or returns input chars
                    If iReadChars < Bytes2Read Then
                    Else
                        '                        ComData = mbytRxBuffer
                        Return (iReadChars)
                    End If
                End If
            Catch ex As Exception

            End Try
        End If
    End Function

    Public Function Input(ByVal mintHandle As Integer, ByVal BytesToRead As Integer) As Integer
        Dim result As Integer
        Dim intResult As Integer
        Dim lpNumberOfBytesRead As Integer = 0
        Try
            If (BytesToRead = 0) Then BytesToRead = mintRXBufferSize