commbase.cs

C#串口编程。详细讲解

			public long InQueueSize {get{return (long)inQueueSize;}}
			/// <summary>
			/// Total size of output queue (0 means information unavailable)
			/// </summary>
			public long OutQueueSize {get{return (long)outQueueSize;}}

			public override string ToString()
			{
				StringBuilder m = new StringBuilder("The reception queue is ", 60);
				if (inQueueSize == 0)
				{
					m.Append("of unknown size and ");
				}
				else
				{
					m.Append(inQueueSize.ToString() + " bytes long and ");
				}
				if (inQueue == 0)
				{
					m.Append("is empty.");
				}
				else if (inQueue == 1)
				{
					m.Append("contains 1 byte.");
				}
				else
				{
					m.Append("contains ");
					m.Append(inQueue.ToString());
					m.Append(" bytes.");
				}
				m.Append(" The transmission queue is ");
				if (outQueueSize == 0)
				{
					m.Append("of unknown size and ");
				}
				else
				{
					m.Append(outQueueSize.ToString() + " bytes long and ");
				}
				if (outQueue == 0)
				{
					m.Append("is empty");
				}
				else if (outQueue == 1)
				{
					m.Append("contains 1 byte. It is ");
				}
				else
				{
					m.Append("contains ");
					m.Append(outQueue.ToString());
					m.Append(" bytes. It is ");
				}
				if (outQueue > 0)
				{
					if (ctsHold || dsrHold || rlsdHold || xoffHold || xoffSent)
					{
						m.Append("holding on");
						if (ctsHold) m.Append(" CTS");
						if (dsrHold) m.Append(" DSR");
						if (rlsdHold) m.Append(" RLSD");
						if (xoffHold) m.Append(" Rx XOff");
						if (xoffSent) m.Append(" Tx XOff");
					}
					else
					{
						m.Append("pumping data");
					}
				}
				m.Append(". The immediate buffer is ");
				if (immediateWaiting)
					m.Append("full.");
				else
					m.Append("empty.");
				return m.ToString();
			}
		}

		/// <summary>
		/// Get the status of the queues
		/// </summary>
		/// <returns>Queue status object</returns>
		protected QueueStatus GetQueueStatus() 
		{
			Win32Com.COMSTAT cs;
			Win32Com.COMMPROP cp;
			uint er;

			CheckOnline();
			if (!Win32Com.ClearCommError(hPort, out er, out cs)) ThrowException("Unexpected failure");
			if (!Win32Com.GetCommProperties(hPort, out cp)) ThrowException("Unexpected failure");
			return new QueueStatus(cs.Flags, cs.cbInQue, cs.cbOutQue, cp.dwCurrentRxQueue, cp.dwCurrentTxQueue);
		}

		// JH 1.3. Added for this version.
		/// <summary>
		/// Test if the line is congested (data being queued for send faster than it is being dequeued)
		/// This detects if baud rate is too slow or if handshaking is not allowing enough transmission
		/// time. It should be called at reasonably long fixed intervals. If data has been sent during
		/// the interval, congestion is reported if the queue was never empty during the interval.
		/// </summary>
		/// <returns>True if congested</returns>
		protected bool IsCongested()
		{
			bool e;
			if (!dataQueued) return false;
			lock(empty) {e = empty[0]; empty[0] = false;}
			dataQueued = false;
			return !e;
		}

		/// <summary>
		/// True if the RTS pin is controllable via the RTS property
		/// </summary>
		protected bool RTSavailable { get { return (stateRTS < 2);}}
		
		/// <summary>
		/// Set the state of the RTS modem control output
		/// </summary>
		protected bool RTS 
		{
			set {
				if (stateRTS > 1) return;
				CheckOnline();
				if (value)
				{
					if (Win32Com.EscapeCommFunction(hPort, Win32Com.SETRTS))
						stateRTS = 1;
					else
						ThrowException("Unexpected Failure");
				}
				else
				{
					if (Win32Com.EscapeCommFunction(hPort, Win32Com.CLRRTS))
						//JH 1.3: Was 1, should be 0:
						stateRTS = 0;
					else
						ThrowException("Unexpected Failure");
				}
			}
			get {
				return (stateRTS == 1);
			}
		}

		/// <summary>
		/// True if the DTR pin is controllable via the DTR property
		/// </summary>
		protected bool DTRavailable { get { return (stateDTR < 2);}}
		
		/// <summary>
		/// The state of the DTR modem control output
		/// </summary>
		protected bool DTR {
			set {
				if (stateDTR > 1) return;
				CheckOnline();
				if (value)
				{
					if (Win32Com.EscapeCommFunction(hPort, Win32Com.SETDTR))
						stateDTR = 1;
					else
						ThrowException("Unexpected Failure");
				}
				else
				{
					if (Win32Com.EscapeCommFunction(hPort, Win32Com.CLRDTR))
						stateDTR = 0;
					else
						ThrowException("Unexpected Failure");
				}
			}
			get {
				return (stateDTR == 1);
			}
		}

		/// <summary>
		/// Assert or remove a break condition from the transmission line
		/// </summary>
		protected bool Break {
			set {
				if (stateBRK > 1) return;
				CheckOnline();
				if (value)
				{
					if (Win32Com.EscapeCommFunction(hPort, Win32Com.SETBREAK))
						stateBRK = 0;
					else
						ThrowException("Unexpected Failure");
				}
				else
				{
					if (Win32Com.EscapeCommFunction(hPort, Win32Com.CLRBREAK))
						stateBRK = 0;
					else
						ThrowException("Unexpected Failure");
				}
			}
			get {
				return (stateBRK == 1);
			}
		}

		/// <summary>
		/// Override this to provide settings. (NB this is called during Open method)
		/// </summary>
		/// <returns>CommBaseSettings, or derived object with required settings initialised</returns>
		protected virtual CommBaseSettings CommSettings() {return new CommBaseSettings();}

		/// <summary>
		/// Override this to provide processing after the port is openned (i.e. to configure remote
		/// device or just check presence).
		/// </summary>
		/// <returns>false to close the port again</returns>
		protected virtual bool AfterOpen() {return true;}

		/// <summary>
		/// Override this to provide processing prior to port closure.
		/// </summary>
		/// <param name="error">True if closing due to an error</param>
		protected virtual void BeforeClose(bool error) {}
		
		/// <summary>
		/// Override this to process received bytes.
		/// </summary>
		/// <param name="ch">The byte that was received</param>
		protected virtual void OnRxChar(byte ch) {}

		/// <summary>
		/// Override this to take action when transmission is complete (i.e. all bytes have actually
		/// been sent, not just queued).
		/// </summary>
		protected virtual void OnTxDone() {}

		/// <summary>
		/// Override this to take action when a break condition is detected on the input line.
		/// </summary>
		protected virtual void OnBreak() {}

		//JH 1.3: Deleted OnRing() which was never called: use OnStatusChange instead (Thanks Jim Foster)

		/// <summary>
		/// Override this to take action when one or more modem status inputs change state
		/// </summary>
		/// <param name="mask">The status inputs that have changed state</param>
		/// <param name="state">The state of the status inputs</param>
		protected virtual void OnStatusChange(ModemStatus mask, ModemStatus state) {}

		/// <summary>
		/// Override this to take action when the reception thread closes due to an exception being thrown.
		/// </summary>
		/// <param name="e">The exception which was thrown</param>
		protected virtual void OnRxException(Exception e) {}

		private void ReceiveThread() {
			byte[] buf = new Byte[1];
			uint gotbytes;
			bool starting;

			starting = true;
			AutoResetEvent sg = new AutoResetEvent(false);
			Win32Com.OVERLAPPED ov = new Win32Com.OVERLAPPED();

			IntPtr unmanagedOv;
			IntPtr uMask;
			uint eventMask = 0;
			unmanagedOv = Marshal.AllocHGlobal(Marshal.SizeOf(ov));
			uMask = Marshal.AllocHGlobal(Marshal.SizeOf(eventMask));

			ov.Offset = 0; ov.OffsetHigh = 0;
			ov.hEvent = sg.Handle;
			Marshal.StructureToPtr(ov, unmanagedOv, true);

			try
			{
				while(true) 
				{
					if (!Win32Com.SetCommMask(hPort, Win32Com.EV_RXCHAR | Win32Com.EV_TXEMPTY | Win32Com.EV_CTS | Win32Com.EV_DSR
						| Win32Com.EV_BREAK | Win32Com.EV_RLSD | Win32Com.EV_RING | Win32Com.EV_ERR))
					{
						throw new CommPortException("IO Error [001]");
					}
					Marshal.WriteInt32(uMask, 0);
					//JH 1.2: Tells the main thread that this thread is ready for action.
					if (starting) {startEvent.Set(); starting = false;}
					if (!Win32Com.WaitCommEvent(hPort, uMask, unmanagedOv)) 
					{
						if (Marshal.GetLastWin32Error() == Win32Com.ERROR_IO_PENDING) 
						{
							sg.WaitOne();
						}
						else
						{
							throw new CommPortException("IO Error [002]");
						}
					}
					eventMask = (uint)Marshal.ReadInt32(uMask);
					if ((eventMask & Win32Com.EV_ERR) != 0)
					{
						UInt32 errs;
						if (Win32Com.ClearCommError(hPort, out errs, IntPtr.Zero))
						{
							//JH 1.2: BREAK condition has an error flag and and an event flag. Not sure if both
							//are always raised, so if CE_BREAK is only error flag ignore it and set the EV_BREAK
							//flag for normal handling. Also made more robust by handling case were no recognised
							//error was present in the flags. (Thanks to Fred Pittroff for finding this problem!)
							int ec = 0;
							StringBuilder s = new StringBuilder("UART Error: ", 40);
							if ((errs & Win32Com.CE_FRAME) != 0) {s = s.Append("Framing,"); ec++;}
							if ((errs & Win32Com.CE_IOE) != 0) {s = s.Append("IO,"); ec++;}
							if ((errs & Win32Com.CE_OVERRUN) != 0) {s = s.Append("Overrun,"); ec++;}
							if ((errs & Win32Com.CE_RXOVER) != 0) {s = s.Append("Receive Cverflow,"); ec++;}
							if ((errs & Win32Com.CE_RXPARITY) != 0) {s = s.Append("Parity,"); ec++;}
							if ((errs & Win32Com.CE_TXFULL) != 0) {s = s.Append("Transmit Overflow,"); ec++;}
							if (ec > 0)
							{
								s.Length = s.Length - 1;
								throw new CommPortException(s.ToString());
							}
							else
							{
								if (errs == Win32Com.CE_BREAK)
								{
									eventMask |= Win32Com.EV_BREAK;
								}
								else
								{
									throw new CommPortException("IO Error [003]");
								}
							}
						}
						else
						{
							throw new CommPortException("IO Error [003]");
						}
					}
					if ((eventMask & Win32Com.EV_RXCHAR) != 0) 
					{
						do 
						{
							gotbytes = 0;
							if (!Win32Com.ReadFile(hPort, buf, 1, out gotbytes, unmanagedOv)) 
							{
								//JH 1.1: Removed ERROR_IO_PENDING handling as comm timeouts have now
								//been set so ReadFile returns immediately. This avoids use of CancelIo
								//which was causing loss of data. Thanks to Daniel Moth for suggesting this
								//might be a problem, and to many others for reporting that it was!

								int x = Marshal.GetLastWin32Error();

								throw new CommPortException("IO Error [004]");
							}
							if (gotbytes == 1) OnRxChar(buf[0]);
						} while (gotbytes > 0);
					}
					if ((eventMask & Win32Com.EV_TXEMPTY) != 0)
					{
						//JH1.3:
						lock(empty) empty[0] = true;
						OnTxDone();
					}
					if ((eventMask & Win32Com.EV_BREAK) != 0) OnBreak();
			
					uint i = 0;
					if ((eventMask & Win32Com.EV_CTS) != 0) i |= Win32Com.MS_CTS_ON;
					if ((eventMask & Win32Com.EV_DSR) != 0) i |= Win32Com.MS_DSR_ON;
					if ((eventMask & Win32Com.EV_RLSD) != 0) i |= Win32Com.MS_RLSD_ON;
					if ((eventMask & Win32Com.EV_RING) != 0) i |= Win32Com.MS_RING_ON;
					if (i != 0)
					{
						uint f;
						if (!Win32Com.GetCommModemStatus(hPort, out f)) throw new CommPortException("IO Error [005]");
						OnStatusChange(new ModemStatus(i), new ModemStatus(f));
					}
				}
			}
			catch (Exception e)
			{
				//JH 1.3: Added for shutdown robustness (Thanks to Fred Pittroff, Mark Behner and Kevin Williamson!), .
				Win32Com.CancelIo(hPort);
				if (uMask != IntPtr.Zero) Marshal.FreeHGlobal(uMask);
				if (unmanagedOv != IntPtr.Zero) Marshal.FreeHGlobal(unmanagedOv);

				if (!(e is ThreadAbortException))
				{
					rxException = e;
					OnRxException(e);
				}
			}
		}

		private bool CheckOnline()
		{
			if ((rxException != null) && (!rxExceptionReported))
			{
				rxExceptionReported = true;
				ThrowException("rx");
			}
			if (online) 
			{