MailMessage message = new MailMessage ();
        message.From = <email>;
        message.To = <email>;
        message.Subject = "Scheduled Power Outage";
        message.Body = "Our servers will be down tonight.";
        SmtpMail.SmtpServer = "localhost";
        SmtpMail.Send (message);


MailMessage and SmtpMail are classes defined in the .NET 
Framework Class Library's  System.Web.Mail namespace.

Due to a security change made to ASP.NET just before it 
shipped,  you need to set SmtpMail's SmtpServer property 
to "localhost" even though "localhost" is  the default.

In addition, you must use the IIS configuration applet to 
enable localhost  (127.0.0.1) to relay messages through the 
local SMTP service.

OR ANOTHER EASY METHOD IS TO WRITE THE pOST METHOD IN THE 
html page or design page .. may b this could be one more 
soln.????

protected void btnsubmit_Click(object sender, EventArgs e
{
System.Net.Mail.MailMessage msg = new
System.Net.Mail.MailMessage(txtfrom.Text, txtname.Text,
txtSubject.Text, txtmessage.Text);

        System.Net.Mail.SmtpClient mysmtp = new
SmtpClient("192.168.1.80");
        try
        {
            mysmtp.Send(msg);
            lblmsg.Text = "mail sent";
        }
        catch (Exception ex)
        {
            lblmsg.Text = ex.Message;
        }
    }
}

protected void btnsubmit_Click(object sender, EventArgs e
{
System.Net.Mail.MailMessage msg = new
System.Net.Mail.MailMessage(txtfrom.Text, txtname.Text,
txtSubject.Text, txtmessage.Text);

        System.Net.Mail.SmtpClient mysmtp = new
SmtpClient("192.168.1.80");
        try
        {
            mysmtp.Send(msg);
            lblmsg.Text = "mail sent";
        }
        catch (Exception ex)
        {
            lblmsg.Text = ex.Message;
        }
    }
}

OR

MailMessage message = new MailMessage ();
        message.From = <email>;
        message.To = <email>;
        message.Subject = "Scheduled Power Outage";
        message.Body = "Our servers will be down tonight.";
        SmtpMail.SmtpServer = "localhost";
        SmtpMail.Send (message);


MailMessage and SmtpMail are classes defined in the .NET 
Framework Class Library's  System.Web.Mail namespace.

Import system.net.mail

Protected sub button_click(ByVal sender as object, ByVal e
as system.EventArgs)handles button.click

dim smtp As New SmtpClient()
smtp.send(New
MailMessage(txtfrom.text,txtto.text,txtsubject.text,txtbody.text))
label.text="Message sent"
End sub

System.Web.Mail.MailMessage obMessage = new 
System.Web.Mail.MailMessage();
obMessage.To = "Receiver@gmail.com";           
obMessage.From = "sender@gmail.com";
obMessage.Subject = strSubject;
obMessage.Body = "Hi! this is the way to send mail;
obMessage.BodyFormat = HTMl;
try
   {
 SmtpMail.SmtpServer = "";
SmtpMail.Send(obMessage);
 bRet = true;
    }
catch (System.Web.HttpException exhttp)
    {
       Trace.Write("Error sending mail " + exhttp.Message);
  }

asp.net is a web based application,so asp.net can send e-
mail from an asp.net application

mailmessage obmail = new mailmessage();
obmail.To= "Dummy@gmail.com";
obmail.from= "sender@gmail.com";
obmail.Subject="Mail sending through web";
obmail.body="Deascription";
try
{
smtp.server="";
smtp.send(obmail);
}
catch(System.Web.HttpException exhttp)
{
trace.write("error sending mail " +exhttp.message);
}

protected void btn_submit_Click(object sender, EventArgs e)
    {
        try
        {
            string rd = "";
            MailMessage mM = new MailMessage();
            mM.From = new MailAddress(Email.Value);
            mM.To.Add("<email>");
            mM.Subject = title.Value;
            if (Radio1.Checked)
            {
                rd = Radio1.Value;
            }
            else
            {
                rd = Radio2.Value;
            }
            mM.Body = rd + "<br>" + name.Value + "<br>" +
title.value + "<br>" + Company.Value + "<br>" + Email.Value
+ "<br>" + url.Value + "<br>" + Comment.Value;
            mM.IsBodyHtml = true;
            mM.Priority = MailPriority.High;
            SmtpClient smtp = new
SmtpClient("smtp.gmail.com", 587);
            smtp.EnableSsl = true;
            smtp.UseDefaultCredentials = false;
            smtp.Credentials = new
NetworkCredential("username", "P@ssword"); //From user
credentails 
            smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
            smtp.Send(mM);
            AlertBox("Mail Send successfully");
        }
        catch 
        {
            AlertBox("Mail Send Failed");
        }
    }