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POC# says "The port is already opened." Fixing it, then "The port is closed." What is wrong with my code?
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copied!<p>I'm trying to put a Serial DataReceivedListener to automate the reading of data from the serial port. Before adding this event, everything works fine.</p> <p>Certain commands cannot continue because C# complains that "The port is already opened." If I comment out "port.Open();", C# then complains that "The port is closed."</p> <p>Here is the code that I think is covered by this whole thing.</p> <pre><code> SerialPort port; String buffer; String[] bufferArray; String tellArduino; // any random one-byte character to "ping" Arduino for a data point Queue<String> date = new Queue<String>(); Queue<String> time = new Queue<String>(); Queue<double> dcGen = new Queue<double>(); public Form1() { // // IDE created this thing // InitializeComponent(); } void port_DataReceived(object sender, SerialDataReceivedEventArgs e) { getDataPoint(); } private void selectPort() { // // Creates new instance of SerialPort with the same // settings as that of the Arduino. Checks if the selected // port can be opened. Catches common exceptions found while debugging // try { port = new SerialPort((string)ports.SelectedItem); port.BaudRate = 9600; port.Parity = Parity.None; port.StopBits = StopBits.One; port.Open(); // check if port can be opened port.Close(); portUsedLabel.Text = (string)ports.SelectedItem; port.DataReceived += new SerialDataReceivedEventHandler(port_DataReceived); getDataPoint(); // called here for testing. Values successfully split } // gotta catch 'em all catch { stuff here } } private void getDataPoint() { /* still incomplete due to debugging phase */ // // Method for getting a data point from the Arduino unit // Pings Arduino unit for a data point. Program then reads // entire serial output until new line (\n) is found. // Program splits the entire buffer in to the bufferArray // and proceeds to distribute each element in to their // respective Queues // buffer = ""; bufferArray = new String[] { "" }; tellArduino = "m"; // any random one-byte string to "ping" Arduino for a data point // it |must| remain exactly one byte to avoid duplicate data port.Open(); port.WriteLine(tellArduino); for (int x = 0; x < tellArduino.Length; x++) { buffer += port.ReadLine(); } port.Close(); // Split each value then add to respective queues bufferArray = buffer.Split(','); date.Enqueue(bufferArray[0]); time.Enqueue(bufferArray[1]); dcGen.Enqueue(double.Parse(bufferArray[2], System.Globalization.CultureInfo.InvariantCulture)); // Start debugging code // adding to ListBox for debugging and checking reasons ports.BeginUpdate(); foreach (String value in bufferArray) { ports.Items.Add(value); } // for testing type double printing ports.Items.Add(dcGen.ElementAt(0)); // ports.EndUpdate(); // End debugging code } </code></pre>

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