Automatic Port Reading

I have solved it myself.
I added a Background Worker.
When you will initialize the Serial Port on Clicking the Start Button, the background worker will start another thread where it will check the value stored in read buffer, if value stored here changes, it will display that value on the TextBox ... Here's My Program, I am posting it for others... so that it may help them.

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;

namespace Serial_Communication
{
    public partial class frmMain : Form
    {
        SerialPort sp;
        byte[] buffer_write,buffer_read;
        bool set = false;
        public frmMain()
        {
            InitializeComponent();
        }

        private void frmMain_Load(object sender, EventArgs e)
        {
            txtPort.MaxLength = 5;
            txtBaudRate.MaxLength = 5;
            txtPort.Text = "COM1";
            txtBaudRate.Text = "9600";
            this.FormClosing += new FormClosingEventHandler(frmMain_FormClosing);
        }

        void consoleBox_KeyPress(object sender, KeyPressEventArgs e)
        {
            buffer_write = BitConverter.GetBytes(e.KeyChar);
            sp.Write(buffer_write, 0, 1);
        }

        void frmMain_FormClosing(object sender, FormClosingEventArgs e)
        {
            MessageBox.Show("Exiting Application");
            try
            {
                backgroundWorker.CancelAsync();
                sp.Close();
            }
            catch (Exception)
            {
            }
        }

        private void exitToolStripMenuItem_Click(object sender, EventArgs e)
        {
            try
            {
                backgroundWorker.CancelAsync();
                sp.Close();
            }
            catch (Exception)
            {
            }
            Application.Exit();
        }

        private void btnStart_Click(object sender, EventArgs e)
        {
            int Number;
            bool isValid;
            isValid = Int32.TryParse(txtBaudRate.Text, out Number);
            if (!isValid)
            {
                MessageBox.Show("Use only Integer for Baud Rate", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
            else if (!set)
            {
                try
                {
                    sp = new SerialPort(txtPort.Text, Number);
                    sp.Open();
                    buffer_write = new byte[2];
                    buffer_read = new byte[2];
                    set = true;
                    backgroundWorker.RunWorkerAsync(sp);
                    btnStart.Text = "Stop";
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message, "Exception", MessageBoxButtons.OK, MessageBoxIcon.Error);
                }
            }
            else
            {
                backgroundWorker.CancelAsync();
                sp.Close();
                btnStart.Text = "Start";
            }
        }

        private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            SerialPort sm = e.Argument as SerialPort;

            while (set)
            {
                if (backgroundWorker.CancellationPending == true)
                {
                    sm.Close();
                    e.Cancel = true;
                    break;
                }
                else
                {
                    try
                    {
                        sm.Read(buffer_read, 0, 1);
                        if (buffer_read[0].ToString() != "")
                        {
                            e.Result = sm;
                            backgroundWorker.ReportProgress(1);
                        }
                    }
                    catch (Exception) { }
                }
            }
        }

        private void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            this.consoleBox.Text += BitConverter.ToChar(buffer_read,0).ToString();
            buffer_read[0] = 0x00;
        }

        private void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Cancelled)
            {
                backgroundWorker.Dispose();
                backgroundWorker = null;
                GC.Collect();
            }
        }
    }
}

This is complete Program created by me. Now I also want to ask a question here, I have setup many exception handlers. Now I am facing a problem while disposing the background worker safely, So, I have added exception handler here. But I doubt it seriously, why these unhandled exceptions are occurring while disposing off the background worker. Please help me regarding this.