RS232 communication, Data received

private string indata;

       private void button1_Click(object sender, EventArgs e)
       {
           try
           {
               serialPort1.PortName = portBox.Text;
               serialPort1.BaudRate = 9600;
               serialPort1.DataBits = 8;
               serialPort1.StopBits = StopBits.One;
               serialPort1.ReadTimeout = -1;
               serialPort1.ReadBufferSize = 4096;
               serialPort1.WriteTimeout = -1;
               serialPort1.Parity = Parity.None;
               serialPort1.Handshake = Handshake.None;
               serialPort1.Open();
               richTextBox1.Text += "HOST1 : Port is open.\r\n";
           }
           catch//(Exception ex)
           {
               richTextBox1.Text += "HOST1 : Port is not open.\r\n";
           }

       }

       private void button2_Click(object sender, EventArgs e)
       {
           serialPort1.Write("\u0005\r\n");
       }

       private void Form1_Load(object sender, EventArgs e)
       {
           portBox.Items.Clear();
           string[] ports = SerialPort.GetPortNames();
           foreach (string Comport in ports)
           {
               portBox.Items.Add(Comport);
           }
       }

       private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
       {
           indata = serialPort1.ReadExisting();

           richTextBox1.Invoke((MethodInvoker)delegate { richTextBox1.Text += "HOST2 : " + indata + "\r\n"; });

       }