private void Button1_Click(object sender, System.EventArgs e)
{
MailMessage mail = new MailMessage(); 
mail.To = txtTo.Text; //put the TO ADDRESS here.
mail.From = txtFrom.Text; //put the FROM ADDRESS here.
mail.Subject = txtSubject.Text; //put the SUBJECT here.
mail.Body = txtBody.Text; //put the BODY here.
SmtpMail.SmtpServer = "localhost"; //put SMTP SERVER you will use here.
SmtpMail.Send(mail); 
}