串口PINVOKE代码，需要对超时时间进行设置，如果全为0，则是无限等待。而不是获取不到退出。
public class SerialWrapper : Idisposable { #region Enum public enum StopBits { None,One,Two,OnePointFive,} public enum Parity { None,Odd,Even,Mark,Space,} #endregion #region Fields /// <summary> /// The baud rate at which the communications device operates. /// </summary> private readonly int iBaudrate; /// <summary> /// The number of bits in the bytes to be transmitted and received. /// </summary> private readonly byte byteSize; /// <summary> /// The system handle to the serial port connection ('file' handle). /// </summary> private IntPtr pHandle = IntPtr.Zero; /// <summary> /// The parity scheme to be used. /// </summary> private readonly Parity parity; /// <summary> /// The name of the serial port to connect to. /// </summary> private readonly string sPortName; /// <summary> /// The number of bits in the bytes to be transmitted and received. /// </summary> private readonly StopBits stopBits; #endregion #region Constructor /// <summary> /// Creates a new instance of SerialCom. /// </summary> /// <param>The name of the serial port to connect to</param> /// <param>The baud rate at which the communications device operates</param> /// <param>The number of stop bits to be used</param> /// <param>The parity scheme to be used</param> /// <param>The number of bits in the bytes to be transmitted and received</param> public SerialWrapper(string portName,int baudrate,StopBits stopBits,Parity parity,byte byteSize) { if (stopBits == StopBits.None) throw new ArgumentException("stopBits cannot be StopBits.None","stopBits"); if (byteSize < 5 || byteSize > 8) throw new ArgumentOutOfRangeException("The number of data bits must be 5 to 8 bits.","byteSize"); if (baudrate < 110 || baudrate > 256000) throw new ArgumentOutOfRangeException("Invalid baud rate specified.","baudrate"); if ((byteSize == 5 && stopBits == StopBits.Two) || (stopBits == StopBits.OnePointFive && byteSize > 5)) throw new ArgumentException("The use of 5 data bits with 2 stop bits is an invalid combination," + "as is 6,7,or 8 data bits with 1.5 stop bits."); this.sPortName = portName; this.iBaudrate = baudrate; this.byteSize = byteSize; this.stopBits = stopBits; this.parity = parity; } /// <summary> /// Creates a new instance of SerialCom. /// </summary> /// <param>The name of the serial port to connect to</param> /// <param>The baud rate at which the communications device operates</param> /// <param>The number of stop bits to be used</param> /// <param>The parity scheme to be used</param> public SerialWrapper(string portName,Parity parity) : this(portName,baudrate,stopBits,parity,8) { } #endregion #region Open /// <summary> /// Opens and initializes the serial connection. /// </summary> /// <returns>Whether or not the operation succeeded</returns> public bool open() { pHandle = CreateFile(this.sPortName,FileAccess.ReadWrite,FileShare.None,IntPtr.Zero,FileMode.Open,IntPtr.Zero); if (pHandle == IntPtr.Zero) return false; if (ConfigureSerialPort()) return true; else { dispose(); return false; } } #endregion #region Write /// <summary> /// Transmits the specified array of bytes. /// </summary> /// <param>The bytes to write</param> /// <returns>The number of bytes written (-1 if error)</returns> public int Write(byte[] data) { FailIfNotConnected(); if (data == null) return 0; int bytesWritten; if (WriteFile(pHandle,data,data.Length,out bytesWritten,0)) return bytesWritten; return -1; } /// <summary> /// Transmits the specified string. /// </summary> /// <param>The string to write</param> /// <returns>The number of bytes written (-1 if error)</returns> public int Write(string data) { FailIfNotConnected(); // convert the string to bytes byte[] bytes; if (data == null) { bytes = null; } else { bytes = Encoding.UTF8.GetBytes(data); } return Write(bytes); } /// <summary> /// Transmits the specified string and appends the carriage return to the end /// if it does not exist. /// </summary> /// <remarks> /// Note that the string must end in '\r\n' before any serial device will interpret the data /// sent. For ease of programmability,this method should be used instead of Write() when you /// want to automatically execute the specified command string. /// </remarks> /// <param>The string to write</param> /// <returns>The number of bytes written (-1 if error)</returns> public int WriteLine(string data) { if (data != null && !data.EndsWith("\r\n")) data += "\r\n"; return Write(data); } #endregion #region Read /// <summary> /// Reads any bytes that have been received and writes them to the specified array. /// </summary> /// <param>The array to write the read data to</param> /// <returns>The number of bytes read (-1 if error)</returns> public int Read(byte[] data) { FailIfNotConnected(); if (data == null) return 0; int bytesRead; if (ReadFile(pHandle,out bytesRead,0)) return bytesRead; return -1; } /// <summary> /// Reads any data that has been received as a string. /// </summary> /// <param>The maximum number of bytes to read</param> /// <returns>The data received (null if no data)</returns> public string ReadString(int maxBytesToRead) { if (maxBytesToRead < 1) throw new ArgumentOutOfRangeException("maxBytesToRead"); byte[] bytes = new byte[maxBytesToRead]; int numBytes = Read(bytes); //string data = ASCIIEncoding.ASCII.GetString(bytes,numBytes); string data = Encoding.UTF8.GetString(bytes,numBytes); return data; } #endregion #region dispose Utils /// <summary> /// disconnects and disposes of the SerialCom instance. /// </summary> public void dispose() { if (pHandle != IntPtr.Zero) { CloseHandle(pHandle); pHandle = IntPtr.Zero; } } /// <summary> /// Flushes the serial I/O buffers. /// </summary> /// <returns>Whether or not the operation succeeded</returns> public bool Flush() { FailIfNotConnected(); const int PURGE_RXCLEAR = 0x0008; // input buffer const int PURGE_TXCLEAR = 0x0004; // output buffer return PurgeComm(pHandle,PURGE_RXCLEAR | PURGE_TXCLEAR); } #endregion #region Private Helpers /// <summary> /// Configures the serial device based on the connection parameters pased in by the user. /// </summary> /// <returns>Whether or not the operation succeeded</returns> private bool ConfigureSerialPort() { DCB serialConfig = new DCB(); if (GetCommState(pHandle,ref serialConfig)) { // setup the DCB struct with the serial settings we need serialConfig.Baudrate = (uint)this.iBaudrate; serialConfig.ByteSize = this.byteSize; serialConfig.fBinary = 1; // must be true serialConfig.fDtrControl = 1; // DTR_CONTROL_ENABLE "Enables the DTR line when the device is opened and leaves it on." serialConfig.fAbortOnError = 0; // false serialConfig.fTXContinueOnXoff = 0; // false serialConfig.fParity = 1; // true so that the Parity member is looked at switch (this.parity) { case Parity.Even: serialConfig.Parity = 2; break; case Parity.Mark: serialConfig.Parity = 3; break; case Parity.Odd: serialConfig.Parity = 1; break; case Parity.Space: serialConfig.Parity = 4; break; case Parity.None: default: serialConfig.Parity = 0; break; } switch (this.stopBits) { case StopBits.One: serialConfig.StopBits = 0; break; case StopBits.OnePointFive: serialConfig.StopBits = 1; break; case StopBits.Two: serialConfig.StopBits = 2; break; case StopBits.None: default: throw new ArgumentException("stopBits cannot be StopBits.None"); } if (SetCommState(pHandle,ref serialConfig)) { // 串口连接超时设置 COMMTIMEOUTS timeouts = new COMMTIMEOUTS(); timeouts.ReadIntervalTimeout = 10; timeouts.ReadTotalTimeoutMultiplier = 10; timeouts.ReadTotalTimeoutConstant = 10; timeouts.WritetotalTimeoutMultiplier = 0; timeouts.WritetotalTimeoutConstant = 0; if (SetCommTimeouts(pHandle,ref timeouts)) { return true; } else { return false; } } else { return false; } } else { return false; } } /// <summary> /// Helper that throws a InvalidOperationException if we don't have a serial connection. /// </summary> private void FailIfNotConnected() { if (pHandle == IntPtr.Zero) throw new InvalidOperationException("You must be connected to the serial port before performing this operation."); } #endregion #region Native Helpers #region Native structures /// <summary> /// Contains the time-out parameters for a communications device. /// </summary> [StructLayout(LayoutKind.Sequential)] struct COMMTIMEOUTS { public uint ReadIntervalTimeout; public uint ReadTotalTimeoutMultiplier; public uint ReadTotalTimeoutConstant; public uint WritetotalTimeoutMultiplier; public uint WritetotalTimeoutConstant; } /// <summary> /// Defines the control setting for a serial communications device. /// </summary> [StructLayout(LayoutKind.Sequential)] struct DCB { public int DCBlength; public uint Baudrate; public uint Flags; public ushort wReserved; public ushort XonLim; public ushort XoffLim; public byte ByteSize; public byte Parity; public byte StopBits; public sbyte XonChar; public sbyte XoffChar; public sbyte ErrorChar; public sbyte EofChar; public sbyte EvtChar; public ushort wReserved1; public uint fBinary; public uint fParity; public uint fOutxCtsFlow; public uint fOutxDsrFlow; public uint fDtrControl; public uint fDsrSensitivity; public uint fTXContinueOnXoff; public uint fOutX; public uint fInX; public uint fErrorChar; public uint fNull; public uint fRtsControl; public uint fAbortOnError; } #endregion #region Native Methods // Used to get a handle to the serial port so that we can read/write to it. [DllImport("kernel32.dll",SetLastError = true,CharSet = CharSet.Auto)] static extern IntPtr CreateFile(string fileName,[MarshalAs(UnmanagedType.U4)] FileAccess fileAccess,[MarshalAs(UnmanagedType.U4)] FileShare fileShare,IntPtr securityAttributes,[MarshalAs(UnmanagedType.U4)] FileMode creationdisposition,int flags,IntPtr template); // Used to close the handle to the serial port. [DllImport("kernel32.dll",SetLastError = true)] static extern bool CloseHandle(IntPtr hObject); // Used to get the state of the serial port so that we can configure it. [DllImport("kernel32.dll")] static extern bool GetCommState(IntPtr hFile,ref DCB lpDCB); // Used to configure the serial port. [DllImport("kernel32.dll")] static extern bool SetCommState(IntPtr hFile,[In] ref DCB lpDCB); // Used to set the connection timeouts on our serial connection. [DllImport("kernel32.dll",SetLastError = true)] static extern bool SetCommTimeouts(IntPtr hFile,ref COMMTIMEOUTS lpCommTimeouts); // Used to read bytes from the serial connection. [DllImport("kernel32.dll")] static extern bool ReadFile(IntPtr hFile,byte[] lpBuffer,int nNumberOfBytesToRead,out int lpNumberOfBytesRead,int lpOverlapped); // Used to write bytes to the serial connection. [DllImport("kernel32.dll",SetLastError = true)] static extern bool WriteFile(IntPtr hFile,int nNumberOfBytesToWrite,out int lpNumberOfBytesWritten,int lpOverlapped); // Used to flush the I/O buffers. [DllImport("kernel32.dll",SetLastError = true)] static extern bool PurgeComm(IntPtr hFile,int dwFlags); #endregion #endregion }
serialPort = new SerialWrapper("com8",14400,SerialWrapper.StopBits.One,SerialWrapper.Parity.None);
serialPort.open();
string s = serialPort.ReadString(100);
this.ShowMessageBox(s);
serialPort.dispose();
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