Reading serial data in ASP.NET

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ASP.NET

RFID

I am trying to read serial data in ASP.NET application but i get an exception ->

"System.NullReferenceException: Object reference not set to an instance of an object."

I have attached my code. Please look into it and tell me how can i read the data. Thanks.

Code--------

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page
{
    private System.IO.Ports.SerialPort serialPort1;
    private System.ComponentModel.IContainer components;

    protected void Page_Load(object sender, EventArgs e)
    {
    }

    private void InitializeComponent()
    {
        this.components = new System.ComponentModel.Container();
        this.serialPort1 = new System.IO.Ports.SerialPort(this.components);
    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        try
        {
            if (serialPort1.IsOpen)
            {
                serialPort1.Close();
            }
            else
            {
                serialPort1.Open();
            }

            Label1.Text += serialPort1.ReadExisting(); //exception here
        }

        catch (Exception eo)
        {          
            Label1.Text = "exception open==>" + eo;
        }         
    }     
}

---------------------------------------------------

P.S. the same code works well in form application.


[Edit member="Tadit"]
Corrected formatting issues.
[/Edit]