下面是一个类：
SetComPara（）方法是设置Com1口的一些参数
OpenCommPort()方法是打开Com1口
CloseComPort（）方法是关闭Com1口
Code
class ComOperation 
{
结构体和dllimport#region 结构体和dllimport //public string PortNum; //1,2,3,4 //public int BaudRate; //1200,2400,4800,9600 //public byte ByteSize; //8 bits //public byte Parity; // 0-4=no,odd,even,mark,space //public byte StopBits; // 0,1,2 = 1, 1.5, 2 //public int ReadTimeout; //10 //设置端口 public string PortNum = "COM1"; //端口 1,2,3,4 //端口设置(默认值，需根据端口情况重新赋值) public int BaudRate = 2400; //1200,2400,4800,9600 每秒位数 public byte ByteSize = 8; //8 bits 数据位 public byte Parity = 0; // 0-4=no,odd,even,mark,space 奇偶效验 public byte StopBits = 0; // 0,1,2 = 1, 1.5, 2 停止位 public int ReadTimeout = 10; //10 //comm port win32 file handle private int hComm = -1; public bool Opened = false; //win32 api constants private const uint GENERIC_READ = 0x80000000; private const uint GENERIC_WRITE = 0x40000000; private const int OPEN_EXISTING = 3; private const int INVALID_HANDLE_VALUE = -1; [StructLayout(LayoutKind.Sequential)] private struct DCB { //taken from c struct in platform sdk public int DCBlength; // sizeof(DCB) public int BaudRate; // current baud rate public int fBinary; // binary mode, no EOF check public int fParity; // enable parity checking public int fOutxCtsFlow; // CTS output flow control public int fOutxDsrFlow; // DSR output flow control public int fDtrControl; // DTR flow control type public int fDsrSensitivity; // DSR sensitivity public int fTXContinueOnXoff; // XOFF continues Tx public int fOutX; // XON/XOFF out flow control public int fInX; // XON/XOFF in flow control public int fErrorChar; // enable error replacement public int fNull; // enable null stripping public int fRtsControl; // RTS flow control public int fAbortOnError; // abort on error public int fDummy2; // reserved public ushort wReserved; // not currently used public ushort XonLim; // transmit XON threshold public ushort XoffLim; // transmit XOFF threshold public byte ByteSize; // number of bits/byte, 4-8 public byte Parity; // 0-4=no,odd,even,mark,space public byte StopBits; // 0,1,2 = 1, 1.5, 2 public char XonChar; // Tx and Rx XON character public char XoffChar; // Tx and Rx XOFF character public char ErrorChar; // error replacement character public char EofChar; // end of input character public char EvtChar; // received event character public ushort wReserved1; // reserved; do not use 
} [StructLayout(LayoutKind.Sequential)] private struct COMMTIMEOUTS { public int ReadIntervalTimeout; public int ReadTotalTimeoutMultiplier; public int ReadTotalTimeoutConstant; public int WriteTotalTimeoutMultiplier; public int WriteTotalTimeoutConstant; } [StructLayout(LayoutKind.Sequential)] private struct OVERLAPPED { public int Internal; public int InternalHigh; public int Offset; public int OffsetHigh; public int hEvent; } [DllImport("kernel32.dll ")] private static extern int CreateFile( string lpFileName, // file name uint dwDesiredAccess, // access mode int dwShareMode, // share mode int lpSecurityAttributes, // SD int dwCreationDisposition, // how to create int dwFlagsAndAttributes, // file attributes int hTemplateFile // handle to template file ); [DllImport("kernel32.dll ")] private static extern bool GetCommState( int hFile, // handle to communications device ref DCB lpDCB // device-control block ); [DllImport("kernel32.dll ")] private static extern bool BuildCommDCB( string lpDef, // device-control string ref DCB lpDCB // device-control block ); [DllImport("kernel32.dll ")] private static extern bool SetCommState( int hFile, // handle to communications device ref DCB lpDCB // device-control block ); [DllImport("kernel32.dll ")] private static extern bool GetCommTimeouts( int hFile, // handle to comm device ref COMMTIMEOUTS lpCommTimeouts // time-out values ); [DllImport("kernel32.dll ")] private static extern bool SetCommTimeouts( int hFile, // handle to comm device ref COMMTIMEOUTS lpCommTimeouts // time-out values ); [DllImport("kernel32.dll ")] private static extern bool ReadFile( int hFile, // handle to file byte[] lpBuffer, // data buffer int nNumberOfBytesToRead, // number of bytes to read ref int lpNumberOfBytesRead, // number of bytes read ref OVERLAPPED lpOverlapped // overlapped buffer ); [DllImport("kernel32.dll ")] private static extern bool WriteFile( int hFile, // handle to file byte[] lpBuffer, // data buffer int nNumberOfBytesToWrite, // number of bytes to write ref int lpNumberOfBytesWritten, // number of bytes written ref OVERLAPPED lpOverlapped // overlapped buffer ); [DllImport("kernel32.dll ")] private static extern bool CloseHandle( int hObject // handle to object ); #endregion 设置端口参数#region 设置端口参数 /**//// <summary> /// 设置端口参数 /// </summary> /// <param name="parPortNum"></param> /// <param name="parBaudRate"></param> /// <param name="parByteSize"></param> /// <param name="parParity"></param> /// <param name="parStopBits"></param> public void SetComPara(string parPortNum, int parBaudRate, byte parByteSize, byte parParity, byte parStopBits) { //设置端口 this.PortNum = parPortNum; //端口 1,2,3,4 this.BaudRate = parBaudRate; //1200,2400,4800,9600 每秒位数 this.ByteSize = parByteSize; //8 bits 数据位 this.Parity = parParity; // 0-4=no,odd,even,mark,space 奇偶效验 this.StopBits = parStopBits; // 0,1,2 = 1, 1.5, 2 停止位 } #endregion 打开Com端口#region 打开Com端口 /**//// <summary> /// 打开Com端口 /// </summary> public void OpenCommPort() { try { DCB dcbCommPort = new DCB(); COMMTIMEOUTS ctoCommPort = new COMMTIMEOUTS(); // OPEN THE COMM PORT. hComm = CreateFile(PortNum, GENERIC_READ | GENERIC_WRITE, 0, 0, OPEN_EXISTING, 0, 0); // IF THE PORT CANNOT BE OPENED, BAIL OUT. if (hComm == INVALID_HANDLE_VALUE) { throw (new ApplicationException("Comm Port Can Not Be Opened ")); } // SET THE COMM TIMEOUTS. GetCommTimeouts(hComm, ref ctoCommPort); ctoCommPort.ReadTotalTimeoutConstant = ReadTimeout; ctoCommPort.ReadTotalTimeoutMultiplier = 0; ctoCommPort.WriteTotalTimeoutMultiplier = 0; ctoCommPort.WriteTotalTimeoutConstant = 0; SetCommTimeouts(hComm, ref ctoCommPort); // SET BAUD RATE, PARITY, WORD SIZE, AND STOP BITS. // THERE ARE OTHER WAYS OF DOING SETTING THESE BUT THIS IS THE EASIEST. // IF YOU WANT TO LATER ADD CODE FOR OTHER BAUD RATES, REMEMBER // THAT THE ARGUMENT FOR BuildCommDCB MUST BE A POINTER TO A STRING. // ALSO NOTE THAT BuildCommDCB() DEFAULTS TO NO HANDSHAKING. dcbCommPort.DCBlength = Marshal.SizeOf(dcbCommPort); GetCommState(hComm, ref dcbCommPort); //将设置的端口参数赋给DCB结构体 dcbCommPort.BaudRate = BaudRate; dcbCommPort.Parity = Parity; dcbCommPort.ByteSize = ByteSize; dcbCommPort.StopBits = StopBits; SetCommState(hComm, ref dcbCommPort); Opened = true; } catch (Exception ex) { throw ex; } } #endregion 关闭Com端口#region 关闭Com端口 /**//// <summary> /// 关闭Com端口 /// </summary> public void CloseComPort() { try { if (hComm != INVALID_HANDLE_VALUE) { CloseHandle(hComm); Opened = false; } } catch (Exception ex) { throw ex; } }
#endregion