ASP.NET

using System;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Net.Mail;

public partial class _Default : System.Web.UI.Page 
{
    #region  "Send email"
    protected void btnSendmail_Click(object sender, EventArgs e)
    {
        // System.Web.Mail.SmtpMail.SmtpServer is obsolete in 2.0
        // System.Net.Mail.SmtpClient is the alternate class for this in 2.0
        SmtpClient smtpClient = new SmtpClient();
        MailMessage message = new MailMessage();

        try
        {
            MailAddress fromAddress = new MailAddress(txtEmail.Text, txtName.Text);

            // You can specify the host name or ipaddress of your server
            // Default in IIS will be localhost 
            smtpClient.Host = "localhost";

            //Default port will be 25
            smtpClient.Port = 25;

            //From address will be given as a MailAddress Object
            message.From = fromAddress;

            // To address collection of MailAddress
            message.To.Add("kn.nageshwaran@gmail.com");
            message.Subject = "Feedback";

            // CC and BCC optional
            // MailAddressCollection class is used to send the email to various users
            // You can specify Address as new MailAddress("admin1@yoursite.com")
            message.CC.Add("admin1@yoursite.com");
            message.CC.Add("admin2@yoursite.com");

            // You can specify Address directly as string
            message.Bcc.Add(new MailAddress("admin3@yoursite.com"));
            message.Bcc.Add(new MailAddress("admin4@yoursite.com"));

            //Body can be Html or text format
            //Specify true if it  is html message
            message.IsBodyHtml = false;

            // Message body content
            message.Body = txtMessage.Text;
         
            // Send SMTP mail
            smtpClient.Send(message);

            lblStatus.Text = "Email successfully sent.";
        }
        catch (Exception ex)
        {
            lblStatus.Text = "Send Email Failed.<br>" + ex.Message;
        }
    }
    #endregion

    #region "Reset"
    protected void btnReset_Click(object sender, EventArgs e)
    {
        txtName.Text = "";
        txtMessage.Text = "";
        txtEmail.Text = "";
    }
    #endregion
}

System.Web.Mail.MailMessage msg = new System.Web.Mail.MailMessage();
        msg.Subject = "Issue Report";
        msg.Body = "Submitted By: " + txtName.Text + "\n";
        msg.Body += txtComment.Text;
        msg.From = txtSender.Text;

        msg.To = txtReceiver.Text;

        if (chkPriority.Checked) msg.Priority = System.Web.Mail.MailPriority.High;

        System.Web.Mail.SmtpMail.SmtpServer = "localhost";
        System.Web.Mail.SmtpMail.Send(msg);

        lblResult.Text = "Message sent to SMTP service.";

System.Web.Mail.SmtpMail.Send(msg);