RS-232 serial communication problem in reading and writing

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.IO.Ports;



namespace Serial_Test
{
    class Program
    {  
        static SerialPort mySerialPort;
        static void Main(string[] args)
        {   
            mySerialPort = new SerialPort("COM3", 9600);

           


            try
            {
                mySerialPort.Open();
                mySerialPort.Write("$01I\r");

                while (true)
                {
                    try
                    {
                        if (mySerialPort.BytesToRead > 0) //if there is data in the buffer
                        {
                            byte b=(byte)mySerialPort.ReadByte(); //read a byte
                            Console.Write(b);
                            mySerialPort.Close();
                        }
                        //other code that can execute without being held up by read method.
                    }
                    catch (IOException ex)
                    {
                        Console.WriteLine(ex);
                        //error handling logic
                    }
                }

               

            }
            catch(IOException ex){

                Console.WriteLine(ex);
           }
        }
        
            }

        

        }