internal static extern Boolean BuildCommDCBAndTimeouts(String lpDef, ref DCB lpDCB, ref COMMTIMEOUTS lpCommTimeouts);
/// <summary> /// Opens the com port and configures it with the required settings /// </summary> /// <returns>false if the port could not be opened</returns> public bool Open() { var portDcb = new DCB(); var commTimeouts = new COMMTIMEOUTS(); var wo = new OVERLAPPED(); if (_online) return false; _hPort = Win32Com.CreateFile(PortName, Win32Com.GENERIC_READ | Win32Com.GENERIC_WRITE, 0, IntPtr.Zero, Win32Com.OPEN_EXISTING, Win32Com.FILE_FLAG_OVERLAPPED, IntPtr.Zero); if (_hPort == (IntPtr)Win32Com.INVALID_HANDLE_VALUE) { if (Marshal.GetLastWin32Error() == Win32Com.ERROR_ACCESS_DENIED) { return false; } throw new CommPortException("Port Open Failure"); } _online = true; commTimeouts.ReadIntervalTimeout = 0; commTimeouts.ReadTotalTimeoutConstant = 0; commTimeouts.ReadTotalTimeoutMultiplier = 0; commTimeouts.WriteTotalTimeoutConstant = SendTimeoutConstant; commTimeouts.WriteTotalTimeoutMultiplier = SendTimeoutMultiplier; portDcb.Init(((Parity == Parity.Odd) || (Parity == Parity.Even)), TxFlowCts, TxFlowDsr, (int)UseDtr, RxGateDsr, !TxWhenRxXoff, TxFlowX, RxFlowX, (int)UseRts); portDcb.BaudRate = BaudRate; portDcb.ByteSize = (byte)DataBits; portDcb.Parity = (byte)Parity; portDcb.StopBits = (byte)StopBits; portDcb.XoffChar = (byte)XoffChar; portDcb.XonChar = (byte)XonChar; portDcb.XoffLim = (short)RxHighWater; portDcb.XonLim = (short)RxLowWater; if ((RxQueue != 0) || (TxQueue != 0)) if (!Win32Com.SetupComm(_hPort, (uint)RxQueue, (uint)TxQueue)) ThrowException("Bad queue settings"); if (!Win32Com.SetCommState(_hPort, ref portDcb)) ThrowException("Bad com settings"); if (!Win32Com.SetCommTimeouts(_hPort, ref commTimeouts)) ThrowException("Bad timeout settings"); _stateBrk = 0; if (UseDtr == HsOutput.None) _stateDtr = 0; if (UseDtr == HsOutput.Online) _stateDtr = 1; if (UseRts == HsOutput.None) _stateRts = 0; if (UseRts == HsOutput.Online) _stateRts = 1; _checkSends = CheckAllSends; wo.Offset = 0; wo.OffsetHigh = 0; wo.hEvent = _checkSends ? _writeEvent.Handle : IntPtr.Zero; _ptrUwo = Marshal.AllocHGlobal(Marshal.SizeOf(wo)); Marshal.StructureToPtr(wo, _ptrUwo, true); _writeCount = 0; _rxException = null; _rxExceptionReported = false; _rxThread = new Thread(ReceiveThread) { Name = "CommBaseRx", Priority = ThreadPriority.AboveNormal }; _rxThread.Start(); Thread.Sleep(1); //Give rx thread time to start. By documentation, 0 should work, but it does not! _auto = false; if (AfterOpen()) { _auto = AutoReopen; return true; } Close(); return false; }
internal static extern Boolean GetCommState(IntPtr hFile, ref DCB lpDCB);