Web.mail.attachment sending mail

using System;
using System.IO;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Web.Mail;


public partial class Web_careers : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
       // clearfields();
    }
    public void clearfields()
    {
        txtName.Text = "";
        txtEmail.Text = "";
        txtcomment.Text = "";
        txtapply.Text = "";
    }

    protected void imgsubmit_Click(object sender, ImageClickEventArgs e)
    {
      
        string sHost = System.Configuration.ConfigurationManager.AppSettings["Host"].ToString();
        string sUserName = System.Configuration.ConfigurationManager.AppSettings["AutorptUser"].ToString();
        string sPassword = System.Configuration.ConfigurationManager.AppSettings["AutorptPassword"].ToString();
        string sFromEmail = System.Configuration.ConfigurationManager.AppSettings["AutorptFromEmail"].ToString();
        int    nPort = Convert.ToInt32(System.Configuration.ConfigurationManager.AppSettings["Port"].ToString());
        bool fSSL = true;

        string MessageBody = "";
        string result = "";
        try
        {
            System.Web.Mail.MailMessage Mail = new System.Web.Mail.MailMessage();
            Mail.Fields["http://schemas.microsoft.com/cdo/configuration/smtpserver"] = sHost;
            Mail.Fields["http://schemas.microsoft.com/cdo/configuration/sendusing"] = 2;

            Mail.Fields["http://schemas.microsoft.com/cdo/configuration/smtpserverport"] = nPort.ToString();
            if (fSSL)
                Mail.Fields["http://schemas.microsoft.com/cdo/configuration/smtpusessl"] = "true";

            if (sUserName.Length == 0)
            {
                //Ingen auth 
            }
            else
            {
                Mail.Fields["http://schemas.microsoft.com/cdo/configuration/smtpauthenticate"] = 1;
                Mail.Fields["http://schemas.microsoft.com/cdo/configuration/sendusername"] = sUserName;
                Mail.Fields["http://schemas.microsoft.com/cdo/configuration/sendpassword"] = sPassword;
            }
           
            string file = fuResume.PostedFile.FileName;
            MessageBody = File.ReadAllText(System.Web.HttpContext.Current.Server.MapPath("../web/careers.txt"));

            MessageBody = MessageBody.Replace("$name$", txtName.Text);
            MessageBody = MessageBody.Replace("$email$", txtEmail.Text);
            MessageBody = MessageBody.Replace("$ApplyFor$", txtapply.Text);
            MessageBody = MessageBody.Replace("$coments$", txtcomment.Text);
            MessageBody = MessageBody.Replace("$Attachment$", file);
           

           
            System.Web.Mail.MailAttachment attachment;
            attachment = new System.Web.Mail.MailAttachment(file);

            Mail.To = txtEmail.Text;
            Mail.From = sFromEmail;
            Mail.Subject = "Enquiry";
            Mail.BodyFormat = System.Web.Mail.MailFormat.Html;
            Mail.Body = MessageBody;

            Mail.Attachments.Add(attachment);


            System.Web.Mail.SmtpMail.SmtpServer = sHost;
            System.Web.Mail.SmtpMail.Send(Mail);
            result = "MailSuccess";
        }
        catch (Exception ex)
        {
            result = ex.Message;
        }
    }
}