title: SerialPort Read Doesn't Work in C#
body: <p>i am develop C# windows app.it's read weight from weigh bridge machine to serial port.but,my code doesn't work.i am trying many examples download from internet doesn't work.my code is below:</p>
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.ComponentModel;
  using System.Data;
  using System.Drawing;
  using System.Linq;
  using System.Text;
  using System.Windows.Forms;
  using System.IO.Ports;
  using System.IO;
  
  namespace SerialPortTest
  {
      public partial class Form1 : Form
      {
          public Form1()
          {
              InitializeComponent();
          }
  
          String a = "";
  
          private void button1_Click(object sender, EventArgs e)
          {
          serialPort1 = new SerialPort("COM1", 9600, Parity.None, 8, StopBits.One);
          if (serialPort1.IsOpen == false)
          {
              serialPort1.Open();
          }
          timer1.Start();
          button1.Enabled = false;
          button2.Enabled = true;
          }
  
          private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
          {
              a = a + serialPort1.ReadExisting();
          }
  
          private void timer1_Tick(object sender, EventArgs e)
          {
              if (a.Length != 0)
              {
                  textBox1.AppendText(a);
                  a = "";
              }
          }
  
          private void button2_Click(object sender, EventArgs e)
          {
              if (serialPort1.IsOpen == true)
              {
                  serialPort1.Close();
                  button2.Enabled = false;
                  button1.Enabled = true;
              }
          }
  
          private void Form1_Load(object sender, EventArgs e)
          {
              if (serialPort1.IsOpen == true)
              {
                  button1.Enabled = false;
                  button2.Enabled = true;
              }
              else
              {
                  button1.Enabled = true;
                  button2.Enabled = false;
              }
          }
      }
  }
  </code></pre>
  
  <p>What i am wrong in my code can any one help me any working code.
  Thanks in Advance. </p>