C# scanning COM ports for specific input

manpreet Best Answer 2 years ago

_x000D_ Firstly, you need to declare new serial port object for each serial port which you create: string[] ports = SerialPort.GetPortNames(); SerialPort[] serialport = new SerialPort[ports.Length]; foreach(string p in ports) { int i = Array.IndexOf(ports, p); serialport[i] = new SerialPort(); //note this line, otherwise you have no serial port declared, only array reference which can contains real SerialPort object serialport[i].PortName = p; serialport[i].BaudRate = 9600; serialport[i].Open(); //Scan inputs for "connectAlready" } And then, you need at least four things to get and to handle your data: Event handler for DataReceived for your serial port serialport[i].DataReceived += serialPort_DataReceived; //This is to add event handler delegate when data is received by the port private void serialPort_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e) { //This is to handle the data when it comes //Do something on data received } Get the data from the underlying stream of the port. private void serialPort_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e) { SerialPort serialPort1 = sender as SerialPort; byte[] data = new byte[serialPort1.BytesToRead]; //this is to provide the data buffer Stream portStream = serialPort1.BaseStream; portStream.Read(data, 0, data.Length); //You get your data from serial port as byte[] //Do something on your data } Encoding.UTF8.GetString to convert the input data from byte[] to ASCII characters (Edit: consider of changing/skip this step and step 2 if the data received is not byte[] but ASCII) private void serialPort_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e) { SerialPort serialPort1 = sender as SerialPort; byte[] data = new byte[serialPort1.BytesToRead]; //this is to provide the data buffer Stream portStream = serialPort1.BaseStream; portStream.Read(data, 0, data.Length); //You get your data from serial port as byte[] string dataString = Encoding.UTF8.GetString(data); //here is your data in string //Do something on your data } Check if the data string contains the data that you want bool hasData = dataString.Contains("connectAlready"); //this is to check if your data has this, if it doesn't do something And as a last note, beware that the data from your serial port doesn't come together (like "conne" and then "ctAlready"). In such case, you need to copy your received data in a global buffer first then have additional checking (use Buffer.BlockCopy) byte[] globalBuffer = new byte[4000]; //large buffer, put globally //In your data received, use Buffer.BlockCopy to copy data to your globalBuffer //Beware the index if (globalBuffer.Length >= 14){ //less than this length, then the data is incomplete //Do the checking if length is at least 14 }