Question

I have device which is connect to PC via USB Serial communication. I am performing following steps

1. Start Device (Power On)
2. Device will detected in my PC as COMx name
3. Start my application
4. On base of COM PID/VID, I connect to device
5. Perform communication. (Up to this I am not facing any problem)
6. when I switch off device, device is disconnected but I cannot able close connection.
7. When I again start(Switch on) device, Device is detected but my application cannot able to connect to COMx(device). It throws IOException "COMx does not exist"

So I think I have some way to close communication port forcefully.

Answer 1

I have found solution though it can not be called standard solution but though i don’t have any problem with that solution because it solves my problem the solution is as per belove step

1. Create class.
2. Create and dispose instance of this class every time you want to send data.

FIRST STEP:-

    class clsRS232 : IDisposable
    {
        private SerialPort myPort;
        public clsRS232()
        {
            myPort = new SerialPort("COM3", 9600, Parity.None, 8, StopBits.One);
        }
        public void OpenPort()
        {
            myPort.Open();
        }
        public void SendFunc(string str)
        {
            myPort.Write(str);
        }
        public string ReadFunc()
        {
           return  myPort.ReadExisting();
        }

        public void Dispose()
        {
            myPort.Dispose();
        }

    }

SECOND STEP:-

using (clsRS232 mySerialPort = new clsRS232())
                    {
                        lock (mySerialPort)
                        {
                            mySerialPort.OpenPort();
                            mySerialPort.SendFunc(commandArg);//here "commandArg" is command or data you want to send to serial port
                            this.serialPortObj_DataReceived(mySerialPort.ReadFunc()); //here "serialPortObj_DataReceived()" is a user define method where received data will be passed
                        }
                    }