在VB新建一个类，把下面的代码复制后即可使用
' ************************************************************************* ' **模 块 名：SerialPort ' **说 明：YFsoft 版权所有2006 - 2007(C) ' **创 建 人：叶帆 ' **日 期：2006-08-17 14:32:29 ' **修 改 人： ' **日 期： ' **描 述：串口异步读写(API) ' **版 本：V1.0.0 ' ************************************************************************* Option Explicit Private Type ComStat fCtsHold As Long fDsrHold As Long fRlsdHold As Long fXoffHold As Long fXoffSent As Long fEof As Long fTxim As Long fReserved As Long cbInQue As Long cbOutQue As Long End Type Private Type COMMTIMEOUTS ReadIntervalTimeout As Long ReadTotalTimeoutMultiplier As Long ReadTotalTimeoutConstant As Long WriteTotalTimeoutMultiplier As Long WriteTotalTimeoutConstant As Long End Type Private Type DCB DCBlength As Long BaudRate As Long ' DWORD DCBlength; /* sizeof(DCB) */ ' DWORD BaudRate; /* Baudrate at which running */ ' DWORD fBinary: 1; /* Binary Mode (skip EOF check) */ ' DWORD fParity: 1; /* Enable parity checking */ ' DWORD fOutxCtsFlow:1; /* CTS handshaking on output */ ' DWORD fOutxDsrFlow:1; /* DSR handshaking on output */ ' DWORD fDtrControl:2; /* DTR Flow control */ ' DWORD fDsrSensitivity:1; /* DSR Sensitivity */ ' DWORD fTXContinueOnXoff: 1; /* Continue TX when Xoff sent */ ' DWORD fOutX: 1; /* Enable output X-ON/X-OFF */ ' DWORD fInX: 1; /* Enable input X-ON/X-OFF */ ' DWORD fErrorChar: 1; /* Enable Err Replacement */ ' DWORD fNull: 1; /* Enable Null stripping */ ' DWORD fRtsControl:2; /* Rts Flow control */ ' DWORD fAbortOnError:1; /* Abort all reads and writes on Error */ ' DWORD fDummy2:17; /* Reserved */ fBitFields As Long ' See Comments in Win32API.Txt wReserved As Integer XonLim As Integer XoffLim As Integer ByteSize As Byte Parity As Byte StopBits As Byte XonChar As Byte XoffChar As Byte ErrorChar As Byte EofChar As Byte EvtChar As Byte wReserved1 As Integer ' Reserved; Do Not Use End Type Private Type OVERLAPPED Internal As Long InternalHigh As Long offset As Long OffsetHigh As Long hEvent As Long End Type Private Type SECURITY_ATTRIBUTES nLength As Long lpSecurityDescriptor As Long bInheritHandle As Long End Type Private Declare Function CloseHandle Lib " kernel32 " ( ByVal hObject As Long ) As Long Private Declare Function GetLastError Lib " kernel32 " () As Long Private Declare Function ReadFile Lib " kernel32 " ( ByVal hFile As Long , lpBuffer As Any, ByVal nNumberOfBytesToRead As Long , lpNumberOfBytesRead As Long , lpOverlapped As OVERLAPPED) As Long Private Declare Function WriteFile Lib " kernel32 " ( ByVal hFile As Long , lpBuffer As Any, ByVal nNumberOfBytesToWrite As Long , lpNumberOfBytesWritten As Long , lpOverlapped As OVERLAPPED) As Long ' OVERLAPPED Private Declare Function SetCommTimeouts Lib " kernel32 " ( ByVal hFile As Long , lpCommTimeouts As COMMTIMEOUTS) As Long Private Declare Function GetCommTimeouts Lib " kernel32 " ( ByVal hFile As Long , lpCommTimeouts As COMMTIMEOUTS) As Long Private Declare Function BuildCommDCB Lib " kernel32 " Alias " BuildCommDCBA " ( ByVal lpDef As String , lpDCB As DCB) As Long Private Declare Function SetCommState Lib " kernel32 " ( ByVal hCommDev As Long , lpDCB As DCB) As Long Private Declare Function GetCommState Lib " kernel32 " ( ByVal nCid As Long , lpDCB As DCB) As Long Private Declare Function CreateFile Lib " kernel32 " Alias " CreateFileA " ( ByVal lpFileName As String , ByVal dwDesiredAccess As Long , ByVal dwShareMode As Long , ByVal lpSecurityAttributes As Long , ByVal dwCreationDisposition As Long , ByVal dwFlagsAndAttributes As Long , ByVal hTemplateFile As Long ) As Long Private Declare Function FlushFileBuffers Lib " kernel32 " ( ByVal hFile As Long ) As Long Private Declare Function CreateEvent Lib " kernel32 " Alias " CreateEventA " (lpEventAttributes As SECURITY_ATTRIBUTES, ByVal bManualReset As Long , ByVal bInitialState As Long , ByVal lpName As String ) As Long Private Declare Function SetCommMask Lib " kernel32 " ( ByVal hFile As Long , ByVal dwEvtMask As Long ) As Long Private Declare Function SetEvent Lib " kernel32 " ( ByVal hEvent As Long ) As Long Private Declare Function PurgeComm Lib " kernel32 " ( ByVal hFile As Long , ByVal dwFlags As Long ) As Long Private Declare Function ClearCommError Lib " kernel32 " ( ByVal hFile As Long , lpErrors As Long , lpStat As ComStat) As Long Private Declare Function GetOverlappedResult Lib " kernel32 " ( ByVal hFile As Long , lpOverlapped As OVERLAPPED, lpNumberOfBytesTransferred As Long , ByVal bWait As Long ) As Long Private Declare Function WaitForSingleObject Lib " kernel32 " ( ByVal hHandle As Long , ByVal dwMilliseconds As Long ) As Long Private Declare Function SetupComm Lib " kernel32 " ( ByVal hFile As Long , ByVal dwInQueue As Long , ByVal dwOutQueue As Long ) As Long Private Const GENERIC_WRITE = & H40000000 Private Const GENERIC_READ = & H80000000 Private Const OPEN_EXISTING = 3 Private Const FILE_ATTRIBUTE_NORMAL = & H80 Private Const FILE_FLAG_OVERLAPPED = & H40000000 Private Const DTR_CONTROL_DISABLE = & H0 Private Const RTS_CONTROL_ENABLE = & H1 Private Const PURGE_RXABORT = & H2 Private Const PURGE_RXCLEAR = & H8 Private Const PURGE_TXABORT = & H1 Private Const PURGE_TXCLEAR = & H4 Private Const ERROR_IO_PENDING = 997 Private Const STATUS_WAIT_0 = & H0 Private Const WAIT_OBJECT_0 = (STATUS_WAIT_0 + 0 ) Private Const WAIT_TIMEOUT = 258 & Private m_Handle As Long Private m_OverlappedRead As OVERLAPPED Private m_OverlappedWrite As OVERLAPPED ' ************************************************************************* ' **函 数 名：OpenPort ' **输 入：ComNumber(Long) - 串口号 ' ** ：Comsettings(String) - 配置信息 ' **输 出：(Long) - 0 成功 非 0 失败 ' **功能描述：打开串口 ' **全局变量： ' **调用模块： ' **作 者：叶帆 ' **日 期：2006-08-17 14:40:14 ' **修 改 人： ' **日 期： ' **版 本：V1.0.0 ' ************************************************************************* Public Function OpenPort(ComNumber As Long , Comsettings As String , Optional lngInSize As Long = 1024 , Optional lngOutSize As Long = 512 ) As Long On Error GoTo handelinitcom Dim retval As Long Dim CtimeOut As COMMTIMEOUTS, dcbs As DCB Dim strCOM As String , strConfig As String strCOM = " /.COM " & Format (ComNumber, " 0 " ) m_Handle = CreateFile(strCOM, GENERIC_READ Or GENERIC_WRITE, 0 , 0 & , OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL Or FILE_FLAG_OVERLAPPED, 0 ) If m_Handle = - 1 Then OpenPort = - 1 Exit Function End If ' 设置dcb块 dcbs.DCBlength = Len (dcbs) ' 长度 Call GetCommState(m_Handle, dcbs) ' 波特率,奇偶校验,数据位,停止位 如：9600,n,8,1 strConfig = " COM " & Format (ComNumber, " 0 " ) & " : " & Comsettings Call BuildCommDCB(strConfig, dcbs) ' ------------------------------ ' dcbs.fBinary = 1 '二进制方式 ' dcbs.fOutxCtsFlow = 0 '不用CTS检测发送流控制 ' dcbs.fOutxDsrFlow = 0 '不用DSR检测发送流控制 ' dcbs.fDtrControl = DTR_CONTROL_DISABLE '禁止DTR流量控制 ' dcbs.fDsrSensitivity = 0 '对DTR信号线不敏感 ' dcbs.fTXContinueOnXoff = 1 '检测接收缓冲区 ' dcbs.fOutX = 0 '不做发送字符控制 ' dcbs.fInX = 0 '不做接收控制 ' dcbs.fErrorChar = 0 '是否用指定字符替换校验错的字符 ' dcbs.fNull = 0 '保留NULL字符 ' dcbs.fRtsControl = RTS_CONTROL_ENABLE '允许RTS流量控制 ' dcbs.fAbortOnError = 0 '发送错误后，继续进行下面的读写操作 ' dcbs.fDummy2 = 0 '保留 dcbs.fBitFields = 1 * 2 ^ 0 Or DTR_CONTROL_DISABLE * 2 ^ 4 Or 1 * 2 ^ 7 Or RTS_CONTROL_ENABLE * 2 ^ 12 dcbs.wReserved = 0 ' 没有使用，必须为0 dcbs.XonLim = 0 ' 指定在XOFF字符发送之前接收到缓冲区中可允许的最小字节数 dcbs.XoffLim = 0 ' 指定在XOFF字符发送之前缓冲区中可允许的最小可用字节数 dcbs.XonChar = 0 ' 发送和接收的XON字符 dcbs.XoffChar = 0 ' 发送和接收的XOFF字符 dcbs.ErrorChar = 0 ' 代替接收到奇偶校验错误的字符 dcbs.EofChar = 0 ' 用来表示数据的结束 dcbs.EvtChar = 0 ' 事件字符，接收到此字符时，会产生一个事件 ' dcbs.wReserved1 = 0 '没有使用 ' dcbs.BaudRate =9600 '波特率 ' dcbs.Parity=0 '奇偶校验 ' dcbs.ByteSize=8 '数据位 ' dcbs.StopBits=0 '停止位 ' ------------------------------ If dcbs.Parity = 0 Then ' 0-4=None,Odd,Even,Mark,Space dcbs.fBitFields = dcbs.fBitFields And & HFFFD ' dcbs.fParity = 0 '奇偶校验无效 Else dcbs.fBitFields = dcbs.fBitFields Or & H2 ' dcbs.fParity = 1 '奇偶校验有效 End If ' 超时设置 CtimeOut.ReadIntervalTimeout = 20 ' 0 CtimeOut.ReadTotalTimeoutConstant = 1 ' 2500 CtimeOut.ReadTotalTimeoutMultiplier = 1 ' 0 CtimeOut.WriteTotalTimeoutConstant = 10 ' 2500 CtimeOut.WriteTotalTimeoutMultiplier = 1 ' 0 retval = SetCommTimeouts(m_Handle, CtimeOut) If retval = - 1 Then retval = GetLastError() OpenPort = retval retval = CloseHandle(m_Handle) Exit Function End If ' 获取信号句柄 Dim lpEventAttributes1 As SECURITY_ATTRIBUTES Dim lpEventAttributes2 As SECURITY_ATTRIBUTES m_OverlappedRead.hEvent = CreateEvent(lpEventAttributes1, 1 , 0 , 0 ) m_OverlappedWrite.hEvent = CreateEvent(lpEventAttributes2, 1 , 0 , 0 ) ' 判断设置参数是否成功 设置输入和输出缓冲区是否成功 If SetCommState(m_Handle, dcbs) = - 1 Or SetupComm(m_Handle, lngInSize, lngOutSize) = - 1 Or m_OverlappedRead.hEvent = 0 Or m_OverlappedWrite.hEvent = 0 Then retval = GetLastError() OpenPort = retval If (m_OverlappedRead.hEvent <> 0 ) Then CloseHandle (m_OverlappedRead.hEvent) If (m_OverlappedWrite.hEvent <> 0 ) Then CloseHandle (m_OverlappedWrite.hEvent) Call CloseHandle(m_Handle) m_Handle = 0 Exit Function End If OpenPort = 0 Exit Function handelinitcom: Call CloseHandle(m_Handle) m_Handle = 0 OpenPort = - 2 Exit Function End Function ' ************************************************************************* ' **函 数 名：ClosePort ' **输 入：无 ' **输 出：(Long) - 0 成功 -1 失败 ' **功能描述：关闭串口 ' **全局变量： ' **调用模块： ' **作 者：叶帆 ' **日 期：2006-08-17 14:56:13 ' **修 改 人： ' **日 期： ' **版 本：V1.0.0 ' ************************************************************************* Public Function ClosePort() As Long If (m_Handle = 0 ) Then ClosePort = 1 Exit Function End If Call SetCommMask(m_Handle, 0 ) Call SetEvent(m_OverlappedRead.hEvent) Call SetEvent(m_OverlappedWrite.hEvent) If (m_OverlappedRead.hEvent <> 0 ) Then CloseHandle (m_OverlappedRead.hEvent) If (m_OverlappedWrite.hEvent <> 0 ) Then CloseHandle (m_OverlappedWrite.hEvent) If CloseHandle(m_Handle) <> 0 Then ClosePort = 0 Else ClosePort = - 1 End If m_Handle = 0 End Function ' ************************************************************************* ' **函 数 名：ClearInBuf ' **输 入：无 ' **输 出：无 ' **功能描述：清空输入缓冲区 ' **全局变量： ' **调用模块： ' **作 者：叶帆 ' **日 期：2006-08-17 14:57:26 ' **修 改 人： ' **日 期： ' **版 本：V1.0.0 ' ************************************************************************* Public Function ClearInBuf() As Long If (m_Handle = 0 ) Then ClearInBuf = 1 Exit Function End If Call PurgeComm(m_Handle, PURGE_RXABORT Or PURGE_RXCLEAR) ClearInBuf = 0 End Function ' ************************************************************************* ' **函 数 名：ClearOutBuf ' **输 入：无 ' **输 出：(Long) - ' **功能描述：清空输出缓冲区 ' **全局变量： ' **调用模块： ' **作 者：叶帆 ' **日 期：2006-08-17 15:40:38 ' **修 改 人： ' **日 期： ' **版 本：V1.0.0 ' ************************************************************************* Public Function ClearOutBuf() As Long If (m_Handle = 0 ) Then ClearOutBuf = 1 Exit Function End If Call PurgeComm(m_Handle, PURGE_TXABORT Or PURGE_TXCLEAR) ClearOutBuf = 0 End Function ' ************************************************************************* ' **函 数 名：SendData ' **输 入：bytBuffer()(Byte) - 数据 ' ** ：lngSize(Long) - 数据长度 ' **输 出：(Long) - ' **功能描述：发送数据 ' **全局变量： ' **调用模块： ' **作 者：叶帆 ' **日 期：2006-08-17 15:43:42 ' **修 改 人： ' **日 期： ' **版 本：V1.0.0 ' ************************************************************************* Public Function SendData(bytBuffer() As Byte , lngSize As Long ) As Long On Error GoTo ToExit ' 打开错误陷阱 ' ------------------------------------------------ If (m_Handle = 0 ) Then SendData = 1 Exit Function End If Dim dwBytesWritten As Long Dim bWriteStat As Long Dim ComStats As ComStat Dim dwErrorFlags As Long dwBytesWritten = lngSize Call ClearCommError(m_Handle, dwErrorFlags, ComStats) bWriteStat = WriteFile(m_Handle, bytBuffer( 0 ), lngSize, dwBytesWritten, m_OverlappedWrite) If bWriteStat = 0 Then If GetLastError() = ERROR_IO_PENDING Then Call GetOverlappedResult(m_Handle, m_OverlappedWrite, dwBytesWritten, 1 ) ' 等待直到发送完毕 End If Else dwBytesWritten = 0 End If SendData = dwBytesWritten ' ------------------------------------------------ Exit Function ' ---------------- ToExit: SendData = - 1 End Function ' ************************************************************************* ' **函 数 名：ReadData ' **输 入：bytBuffer()(Byte) - 数据 ' ** ：lngSize(Long) - 数据长度 ' **输 出：(Long) - ' **功能描述：读取数据 ' **全局变量： ' **调用模块： ' **作 者：叶帆 ' **日 期：2006-08-17 16:04:38 ' **修 改 人： ' **日 期： ' **版 本：V1.0.0 ' ************************************************************************* Public Function ReadData(bytBuffer() As Byte , lngSize As Long , Optional Overtime As Long = 3000 ) As Long On Error GoTo ToExit ' 打开错误陷阱 ' ------------------------------------------------ If (m_Handle = 0 ) Then ReadData = 1 Exit Function End If Dim lngBytesRead As Long Dim fReadStat As Long Dim dwRes As Long lngBytesRead = lngSize ' 读数据 fReadStat = ReadFile(m_Handle, bytBuffer( 0 ), lngSize, lngBytesRead, m_OverlappedRead) If fReadStat = 0 Then If GetLastError() = ERROR_IO_PENDING Then ' 重叠 I/O 操作在进行中 dwRes = WaitForSingleObject(m_OverlappedRead.hEvent, Overtime) ' 等待，直到超时 Select Case dwRes Case WAIT_OBJECT_0: ' 读完成 If GetOverlappedResult(m_Handle, m_OverlappedRead, lngBytesRead, 0 ) = 0 Then ' 错误 ReadData = - 2 Exit Function End If Case WAIT_TIMEOUT: ' 超时 ReadData = - 1 Exit Function Case Else : ' WaitForSingleObject 错误 End Select End If End If ReadData = lngBytesRead ' ------------------------------------------------ Exit Function ' ---------------- ToExit: ReadData = - 1 End Function ' ************************************************************************* ' **函 数 名：Class_Terminate ' **输 入：无 ' **输 出：无 ' **功能描述： ' **全局变量： ' **调用模块： ' **作 者：叶帆 ' **日 期：2006-08-17 16:36:21 ' **修 改 人： ' **日 期： ' **版 本：V1.0.0 ' ************************************************************************* Private Sub Class_Terminate() Call ClosePort End Sub
