CODEWITHSUNDEEP
c#serial-port
Patrick Kerr
Patrick Kerr

Reputation: 23

Serial Port Connection, Readline/ReadExisting Does Not Work

I'm trying to make a serial connection to another machine. I'm using a Virtual Serial Port Emulator to try this. The settings that I use on hyperterminal are like the ones below. I can see the portopen is true, but I can't check whether I can write or read. When I try the ReadLine method it gives TimeoutException and when it's readExisting command it does nothing. DataReceived is never triggered too. Can you help me out with that ? 

 private void Page1_Load(object sender, EventArgs e)
        {

        //Port name can be identified by checking the ports


        // section in Device Manager after connecting your device
        serialPort1.PortName = "COM14"; // that one works for me

        //Provide the name of port to which device is connected

        //default values of hardware[check with device specification document]
        serialPort1.BaudRate = 115200;
        serialPort1.Parity = Parity.None;
        serialPort1.DataBits = 8;
        serialPort1.StopBits = StopBits.One;
        serialPort1.Handshake = Handshake.None;
        serialPort1.RtsEnable = true;
        serialPort1.DtrEnable = true;
        serialPort1.ReceivedBytesThreshold = 8;
        serialPort1.ReadTimeout = 2000;
        serialPort1.DataReceived += new SerialDataReceivedEventHandler(serialPort1_DataReceived);  //
        // Writes data to the Serial Port output buffer 

        //opens the port
        serialPort1.Open();
    }

      private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
    {


        inputData = serialPort1.ReadExisting();
        this.Invoke((MethodInvoker)delegate { DoUpdate(); });


    }

     public void DoUpdate()
    {
        textOutput.Text = (textOutput.Text + inputData);

    }

     private void btnReadExist_Click(object sender, EventArgs e)
    {

        if ((serialPort1.IsOpen == true))
        {


           serialPort1.WriteLine("something"); 
           string read= serialPort1.ReadExisting();
           //string output = serialPort1.ReadLine();
           textOutput.Text += read;

        }
    }


    private void Page1_FormClosed(object sender,System.Windows.Forms.FormClosedEventArgs e)
    {
        //  Close the Serial Port
          serialPort1.Close();
    }

Upvotes: 1

Views: 3394

Answers (1)

Thorsten Dittmar
Thorsten Dittmar

Reputation: 56697

The problem seems to be that you're reading in two code blocks: first, directly after sending the text in the button's event. Secondly you have an event assigned that reads data when called asynchronously. You should decide which one to use and remove the other.

Upvotes: 0

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