port.cs

C#串口通讯开发实例一个基于C#开发的串口通讯实例

			dcb.fErrorChar = portSettings.ReplaceErrorChar;
			dcb.fInX = portSettings.InX;
			dcb.fNull = portSettings.DiscardNulls;
			dcb.fOutX = portSettings.OutX;
			dcb.fOutxCtsFlow = portSettings.OutCTS;
			dcb.fOutxDsrFlow = portSettings.OutDSR;
			dcb.fParity = (portSettings.BasicSettings.Parity == Parity.none) ? false : true;
			dcb.fRtsControl = (DCB.RtsControlFlags)portSettings.RTSControl;
			dcb.fTXContinueOnXoff = portSettings.TxContinueOnXOff;
			dcb.Parity = (byte)portSettings.BasicSettings.Parity;

			dcb.StopBits = (byte)portSettings.BasicSettings.StopBits;
			dcb.XoffChar = (sbyte)portSettings.XoffChar;
			dcb.XonChar = (sbyte)portSettings.XonChar;

			dcb.XonLim = dcb.XoffLim = (ushort)(rxBufferSize / 10);

			m_CommAPI.SetCommState(hPort, dcb);

			// store some state values
			brk = 0;
			dtr = dcb.fDtrControl == DCB.DtrControlFlags.Enable ? 1 : 0;
			rts = dcb.fRtsControl == DCB.RtsControlFlags.Enable ? 1 : 0;

			// set the Comm timeouts
			CommTimeouts ct = new CommTimeouts();

			// reading we'll return immediately
			// this doesn't seem to work as documented
			ct.ReadIntervalTimeout = uint.MaxValue; // this = 0xffffffff
			ct.ReadTotalTimeoutConstant = 0;
			ct.ReadTotalTimeoutMultiplier = 0;

			// writing we'll give 5 seconds
			ct.WriteTotalTimeoutConstant = 5000;
			ct.WriteTotalTimeoutMultiplier = 0;

			m_CommAPI.SetCommTimeouts(hPort, ct);

			// read the ports capabilities
			bool status=GetPortProperties();

			// start the receive thread
			eventThread = new Thread(new ThreadStart(CommEventThread));
			eventThread.Priority = ThreadPriority.Highest;
			eventThread.Start();

			// wait for the thread to actually get spun up
			threadStarted.WaitOne();

			return true;
		}

		/// <summary>
		/// Query the current port's capabilities without accessing it. You can only call the Close()
		/// method after reading the capabilities. This method does neither initialize nor Open() the
		/// port.
		/// </summary>
		///
		/// <example>
		///
		/// </example>
		public bool Query()
		{
			if(isOpen) return false;

			hPort = m_CommAPI.QueryFile(portName);

			if(hPort == (IntPtr)CommAPI.INVALID_HANDLE_VALUE)
			{
				int e = Marshal.GetLastWin32Error();

				if(e == (int)APIErrors.ERROR_ACCESS_DENIED)
				{
					// port is unavailable
					return false;
				}

				// ClearCommError failed!
				string error = String.Format("CreateFile Failed: {0}", e);
				throw new CommPortException(error);
			}


			// read the port's capabilities
			bool status=GetPortProperties();

			return true;
		}

		// parameters without closing and reopening the port
		/// <summary>
		/// Updates communication settings of the port
		/// </summary>
		/// <returns>true if successful, false if it fails</returns>
		private bool UpdateSettings()
		{
			if(!isOpen) return false;

			// transfer the port settings to a DCB structure
			dcb.BaudRate = (uint)portSettings.BasicSettings.BaudRate;
			dcb.ByteSize = portSettings.BasicSettings.ByteSize;
			dcb.EofChar = (sbyte)portSettings.EOFChar;
			dcb.ErrorChar = (sbyte)portSettings.ErrorChar;
			dcb.EvtChar = (sbyte)portSettings.EVTChar;
			dcb.fAbortOnError = portSettings.AbortOnError;
			dcb.fBinary = true;
			dcb.fDsrSensitivity = portSettings.DSRSensitive;
			dcb.fDtrControl = (DCB.DtrControlFlags)portSettings.DTRControl;
			dcb.fErrorChar = portSettings.ReplaceErrorChar;
			dcb.fInX = portSettings.InX;
			dcb.fNull = portSettings.DiscardNulls;
			dcb.fOutX = portSettings.OutX;
			dcb.fOutxCtsFlow = portSettings.OutCTS;
			dcb.fOutxDsrFlow = portSettings.OutDSR;
			dcb.fParity = (portSettings.BasicSettings.Parity == Parity.none) ? false : true;
			dcb.fRtsControl = (DCB.RtsControlFlags)portSettings.RTSControl;
			dcb.fTXContinueOnXoff = portSettings.TxContinueOnXOff;
			dcb.Parity = (byte)portSettings.BasicSettings.Parity;
			dcb.StopBits = (byte)portSettings.BasicSettings.StopBits;
			dcb.XoffChar = (sbyte)portSettings.XoffChar;
			dcb.XonChar = (sbyte)portSettings.XonChar;

			dcb.XonLim = dcb.XoffLim = (ushort)(rxBufferSize / 10);

			return m_CommAPI.SetCommState(hPort, dcb);

		}

		/// <summary>
		/// Close the current serial port
		/// </summary>
		/// <returns>true indicates success, false indicated failure</returns>
		public bool Close()
		{

			if(txOverlapped != IntPtr.Zero)
			{
				LocalFree(txOverlapped);
				txOverlapped = IntPtr.Zero;
			}

			if(!isOpen) return false;

			isOpen = false; // to help catch intentional close

			if(m_CommAPI.CloseHandle(hPort))
			{
				m_CommAPI.SetEvent(closeEvent);

				isOpen = false;

				hPort = (IntPtr)CommAPI.INVALID_HANDLE_VALUE;

				m_CommAPI.SetEvent(closeEvent);

				return true;
			}

			return false;
		}

		/// <summary>
		/// The Port's output buffer.  Set this property to send data.
		/// </summary>
		public byte[] Output
		{
			set
			{
				if(!isOpen)
					throw new CommPortException("Port not open");

				int written = 0;

				// more than threshold amount so send without buffering
				if(value.GetLength(0) > sthreshold)
				{
					// first send anything already in the buffer
					if(ptxBuffer > 0)
					{
						m_CommAPI.WriteFile(hPort, txBuffer, ptxBuffer, ref written, txOverlapped);
						ptxBuffer = 0;
					}

					m_CommAPI.WriteFile(hPort, value, (int)value.GetLength(0), ref written, txOverlapped);
				}
				else
				{
					// copy it to the tx buffer
					value.CopyTo(txBuffer, (int)ptxBuffer);
					ptxBuffer += (int)value.Length;

					// now if the buffer is above sthreshold, send it
					if(ptxBuffer >= sthreshold)
					{
						m_CommAPI.WriteFile(hPort, txBuffer, ptxBuffer, ref written, txOverlapped);
						ptxBuffer = 0;
					}
				}
			}
		}

		/// <summary>
		/// The Port's input buffer.  Incoming data is read from here and a read will pull InputLen bytes from the buffer
		/// <seealso cref="InputLen"/>
		/// </summary>
		public byte[] Input
		{
			get
			{
				if(!isOpen) return null;

				int dequeueLength = 0;

				// lock the rx FIFO while reading
				rxBufferBusy.WaitOne();

				// how much data are we *actually* going to return from the call?
				if(inputLength == 0)
					dequeueLength = rxFIFO.Count;  // pull the entire buffer
				else
					dequeueLength = (inputLength < rxFIFO.Count) ? inputLength : rxFIFO.Count;

				byte[] data = new byte[dequeueLength];

				// dequeue the data
				for(int p = 0 ; p < dequeueLength ; p++)
					data[p] = (byte)rxFIFO.Dequeue();

				// release the mutex so the Rx thread can continue
				rxBufferBusy.ReleaseMutex();

				return data;
			}
		}

		/// <summary>
		/// The length of the input buffer
		/// </summary>
		public int InputLen
		{
			get
			{
				return inputLength;
			}
			set
			{
				inputLength = value;
			}
		}

		/// <summary>
		/// The actual amount of data in the input buffer
		/// </summary>
		public int InBufferCount
		{
			get
			{
				if(!isOpen) return 0;

				return rxFIFO.Count;
			}
		}

		/// <summary>
		/// The actual amount of data in the output buffer
		/// </summary>
		public int OutBufferCount
		{
			get
			{
				if(!isOpen) return 0;

				return ptxBuffer;
			}
		}

		/// <summary>
		/// The number of bytes that the receive buffer must exceed to trigger a Receive event
		/// </summary>
		public int RThreshold
		{
			get
			{
				return rthreshold;
			}
			set
			{
				rthreshold = value;
			}
		}

		/// <summary>
		/// The number of bytes that the transmit buffer must exceed to trigger a Transmit event
		/// </summary>
		public int SThreshold
		{
			get
			{
				return sthreshold;
			}
			set
			{
				sthreshold = value;
			}
		}

		/// <summary>
		/// Send or check for a communications BREAK event
		/// </summary>
		public bool Break
		{
			get
			{
				if(!isOpen) return false;

				return (brk == 1);
			}
			set
			{
				if(!isOpen) return;
				if(brk < 0) return;
				if(hPort == (IntPtr)CommAPI.INVALID_HANDLE_VALUE) return;

				if (value)
				{
					if (m_CommAPI.EscapeCommFunction(hPort, CommEscapes.SETBREAK))
						brk = 1;
					else
						throw new CommPortException("Failed to set break!");
				}
				else
				{
					if (m_CommAPI.EscapeCommFunction(hPort, CommEscapes.CLRBREAK))
						brk = 0;
					else
						throw new CommPortException("Failed to clear break!");
				}
			}
		}

		/// <summary>
		/// Returns whether or not the current port support a DTR signal
		/// </summary>
		public bool DTRAvailable
		{
			get
			{
				return dtravail;
			}
		}

		/// <summary>
		/// Gets or sets the current DTR line state (true = 1, false = 0)
		/// </summary>
		public bool DTREnable
		{
			get
			{
				return (dtr == 1);
			}
			set
			{
				if(dtr < 0) return;
				if(hPort == (IntPtr)CommAPI.INVALID_HANDLE_VALUE) return;

				if (value)
				{
					if (m_CommAPI.EscapeCommFunction(hPort, CommEscapes.SETDTR))
						dtr = 1;
					else
						throw new CommPortException("Failed to set DTR!");
				}
				else
				{
					if (m_CommAPI.EscapeCommFunction(hPort, CommEscapes.CLRDTR))
						dtr = 0;
					else
						throw new CommPortException("Failed to clear DTR!");
				}
			}
		}