logfile in c#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.IO;

namespace logfile
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        SqlConnection _con = new SqlConnection("Data Source=db205.my-hosting-panel.com;Initial Catalog=goggery_sample;User ID=goggery_sample;Password=sample1.0");
        protected void Page_Load(object sender, EventArgs e)
        {

        }
     

        public void LogFile(string sExceptionName, string sEventName, string sFormName)
        {

            StreamWriter log;

            if (!File.Exists("logfile.txt"))
            {

                log = new StreamWriter("E:\\nandu\\logfile.txt");

            }

            else
            {

                log = File.AppendText("E:\\nandu\\logfile.txt");

            }

            // Write to the file:

            log.WriteLine("Data Time:" + DateTime.Now);

            log.WriteLine("Exception Name:" + sExceptionName);

            log.WriteLine("Event Name:" + sEventName);

            //log.WriteLine("Control Name:" + sControlName);

            //log.WriteLine("Error Line No.:" + nErrorLineNo);

            log.WriteLine("Form Name:" + sFormName);

            // Close the stream:

            log.Close();

        }
       

        protected void btnsubmit_Click(object sender, EventArgs e)
        {
            try
            {
                SqlCommand _cmd = new SqlCommand("insert into log_nandu values('" + txtname.Text + "','" + txtcourse.Text + "','" + txtfee.Text + "')", _con);
                _con.Open();
                _cmd.ExecuteNonQuery();
                _con.Close();
            }
            catch (Exception exe)
            {

                //call LogFile method and pass argument as Exception message, event name, control         name, error line number, current form name

                LogFile(exe.Message, exe.ToString(),this.Page.ToString());

            }
        }


    }
}