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POserialport responding to EventHandler, but not ReadExisting or ReadLine?
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copied!<p>i have a program that's reading from serial port in c#. i need to quickly write to a port, read from it, then close it. i cannot leave it open. i understand that serial ports read and write slowly, I've tried to set the ReadTimeout and WriteTimeout properties high, and added a thread.Sleep to try to drag the read and write times out for the devices. here's a little bit of code:</p> <p>my method to write to port:</p> <pre><code> private void CheckPorts(string testMessage) { foreach (string s in SerialPort.GetPortNames()) { portNumber = Int32.Parse(s.Remove(0, 3)); testSerial = new SerialPort(s, baudRate, Parity.None, 8, StopBits.One); if (testSerial.IsOpen) { testSerial.Close(); } testSerial.ReadTimeout = 2000; testSerial.WriteTimeout = 1000; testSerial.Open(); if (testSerial.IsOpen) { string received; testSerial.DiscardInBuffer(); try { //testSerial.DataReceived += new SerialDataReceivedEventHandler(testSerialPort_DataReceived); testSerial.Write(testMessage); System.Threading.Thread.Sleep(2000); received = testSerial.ReadExisting(); //EITHER I USE THIS OR EVENT HANDLER, NOT BOTH } catch (TimeoutException e) { testSerial.Close(); continue; } if (received.Length > 0) { MessageReceived(received); } testSerial.Close(); } } } private void testSerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e) { string received = testSerial.ReadExisting(); int y = received.IndexOf("\r"); while (y == -1) { received = received + testSerial.ReadExisting(); y = received.IndexOf("\r"); } if (testSerial.IsOpen) { testSerial.Close(); } } </code></pre> <p>i'm wondering, if i absolutely have to use datahandler, how do i keep the serial port open long enough to read from it, but close the serialport before the next port needs to be opened?</p> <p>see, the first method gets called a few times, and it iterates through a foreach loop, trying a message on a few ports, then trying to read a response. so, at some point i have to close the ports, or else the next time it goes through it, it doesn't work properly because the port is still open</p> <p>HERE'S MY UPDATED CODE (still not working):</p> <pre><code> private void CheckPorts(string testMessage, int baudRate) { foreach (string s in SerialPort.GetPortNames()) { var interval = 3000; // ms var timer = new System.Timers.Timer(interval); timer.Elapsed += (o, e) => { timer.Enabled = false; if (testSerial.IsOpen) testSerial.Close(); // may not be necessary with Dispose? testSerial.Dispose(); timer.Dispose(); }; portNumber = Int32.Parse(s.Remove(0, 3)); testSerial = new SerialPort(s, baudRate, Parity.None, 8, StopBits.One); testSerial.ReadTimeout = 2000; testSerial.WriteTimeout = 2000; if (testSerial.IsOpen) { testSerial.Close(); } testSerial.Open(); timer.Enabled = true; if (testSerial.IsOpen) { string received; //testSerial.DiscardInBuffer(); //autoEvent = new AutoResetEvent(false); try { // testSerial.DataReceived += new SerialDataReceivedEventHandler(testSerialPort_DataReceived); // autoEvent.Reset(); lblPortNum.Content = s; lblPortNum.Refresh(); testSerial.Write(testMessage); //System.Threading.Thread.Sleep(2000); //testSerial.NewLine = "\r\n"; byte[] rBuff = new byte[2]; int rCnt = testSerial.Read(rBuff, 0, 2); System.Text.Encoding enc = System.Text.Encoding.ASCII; received = enc.GetString(rBuff); //received = testSerial.ReadLine(); } catch (TimeoutException e) { testSerial.Close(); continue; } if (received.Length > 0) { MessageReceived(received, Int16.Parse(s.Remove(0, 3))); } /* if (autoEvent.WaitOne(2000)) { // the port responded // testSerial.Close(); autoEvent.Dispose(); lblPortNum.Content = "HEY I RESPONDED"; } else { testSerial.Close(); autoEvent.Dispose(); continue; // port did not respond within 2 seconds }*/ //testSerial.Close(); } } } </code></pre> <p>UPDATED AGAIN (still not working properly)</p> <pre><code>private void CheckPorts(string testMessage, int baudRate) { foreach (string s in SerialPort.GetPortNames()) { portNumber = Int32.Parse(s.Remove(0, 3)); // MUST BE LOCAL var serialOneOfMany = new SerialPort(s, baudRate, Parity.None, 8, StopBits.One); serialOneOfMany.ReadTimeout = 2000; serialOneOfMany.WriteTimeout = 2000; if (serialOneOfMany.IsOpen) { serialOneOfMany.Close(); } // timer must be defined _after_ serialOneOfMany var interval = 3000; // ms var timer = new System.Timers.Timer(interval); timer.Elapsed += (o, e) => { timer.Enabled = false; if (serialOneOfMany.IsOpen) serialOneOfMany.Close(); // may not be necessary with Dispose? serialOneOfMany.Dispose(); timer.Dispose(); }; if (serialOneOfMany.IsOpen) { string received; try { lblPortNum.Content = s; lblPortNum.Refresh(); serialOneOfMany.Write(testMessage); byte[] rBuff = new byte[2]; int rCnt = serialOneOfMany.Read(rBuff, 0, 2); System.Text.Encoding enc = System.Text.Encoding.ASCII; received = enc.GetString(rBuff); } catch (TimeoutException e) { serialOneOfMany.Close(); continue; } if (received.Length > 0) { CheckIfTheMessageMatches(received, Int16.Parse(s.Remove(0, 3))); } } } } </code></pre> <p>so with this update, it just blows through the code, i can step through the code line by line, but it doesn't stop for 3 seconds at all. if i run it without any debugging breaks, it just goes through it i a fraction of a second</p> <p>UPDATE 10-25-11</p> <pre><code> private void CheckPorts(string testMessage, int baudRate) { foreach (string s in SerialPort.GetPortNames()) { string received = ""; testSerial = new SerialPort(s,baudRate, Parity.None, 8, StopBits.One); lblStatus.Content = "Scanning..."; lblStatus.Refresh(); if (testSerial.IsOpen) { testSerial.Close(); } else { testSerial.Open(); } if (testSerial.IsOpen) { try { testSerial.NewLine = "\r"; lblPortNum.Content = s; lblPortNum.Refresh(); testSerial.WriteTimeout= 500; testSerial.ReadTimeout = 1000; testSerial.WriteLine(testMessage); System.Threading.Thread.Sleep(500); /*THIS DOESN'T WORK byte[] buffer = new byte[testSerial.BytesToRead]; int rCnt = testSerial.Read(buffer, 0, buffer.Length); received = enc.GetString(buffer);*/ //received = Convert.ToString(testSerial.BaseStream.Read(buffer, 0, (int)buffer.Length)); received = testSerial.ReadLine(); int y = received.IndexOf("\r"); while (y == -1) { received = received + testSerial.ReadExisting(); y = received.Length; } if (lblInfo.Dispatcher.Thread == Thread.CurrentThread) { CheckIfTheMessageMatches(received, s); received = received + lblInfo.Content; lblInfo.Content = received; } else { lblInfo.Dispatcher.Invoke(DispatcherPriority.Normal, new ThreadCheck(threadCheck), received); } if (testSerial.IsOpen) { testSerial.Close(); } /*I USE THIS WITH THE sPort.Read() METHOD while (rCnt > 0) { if (lblInfo.Dispatcher.Thread == Thread.CurrentThread) { CheckIfTheMessageMatches(received, s); rCnt = 0; received = received + lblInfo.Content; lblInfo.Content = received; } else { lblInfo.Dispatcher.Invoke(DispatcherPriority.Normal, new ThreadCheck(threadCheck), received); } } */ if (testSerial.IsOpen) { testSerial.Close(); } } catch (TimeoutException e) { testSerial.Close(); continue; } received = null; } } lblStatus.Content = "Finished Scanning."; lblPortNum.Content = ""; } </code></pre> <p>UPDATED CODE here's some new code, still not working, dataeventhandler not even called once. i know it's getting messages because i have another program that works with the serial devices</p> <pre><code>private void CheckPorts(string testMessage, int baudRate) { foreach (string s in SerialPort.GetPortNames()) { var serialOneOfMany = new SerialPort(s, baudRate, Parity.None, 8, StopBits.One); serialOneOfMany.ReadTimeout = 700; serialOneOfMany.WriteTimeout = 100; var interval = 500; // ms var timer = new System.Timers.Timer(interval); timer.Elapsed += (o, e) => { timer.Enabled = false; if (serialOneOfMany.IsOpen) serialOneOfMany.Close(); // may not be necessary with Dispose? serialOneOfMany.Dispose(); timer.Dispose(); }; timer.Enabled = true; lblStatus.Content = "Scanning..."; lblStatus.Refresh(); if (serialOneOfMany.IsOpen) { serialOneOfMany.Close(); } else { serialOneOfMany.Open(); } if (serialOneOfMany.IsOpen) { string received; try { lblPortNum.Content = s; lblPortNum.Refresh(); serialOneOfMany.WriteLine(testMessage); System.Threading.Thread.Sleep(400); serialOneOfMany.DataReceived += new SerialDataReceivedEventHandler(testSerialPort_DataReceived); } catch (TimeoutException e) { serialOneOfMany.Close(); continue; } } } lblStatus.Content = "Finished Scanning."; lblPortNum.Content = ""; } private void testSerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e) { SerialPort receivingSerial = sender as SerialPort; string received = receivingSerial.ReadExisting(); int y = received.IndexOf("\r"); while (y == -1) { received = received + receivingSerial.ReadExisting(); y = received.IndexOf("\r"); } if (lblInfo.Dispatcher.Thread == Thread.CurrentThread) { string name = receivingSerial.PortName; received = received + lblInfo.Content; lblInfo.Content = received; CheckIfTheMessageMatches(received, name); } else { lblInfo.Dispatcher.Invoke(DispatcherPriority.Normal, new ThreadCheck(threadCheck), received); } if (receivingSerial.IsOpen) { receivingSerial.Close(); } } </code></pre>

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