using System.Web.Mail;


 string body = "Hi this is a sample mail";
        
        
       
        MailMessage m = new MailMessage();
        m.Body = body;
        m.BodyFormat = MailFormat.Html;
        m.To = "abc@gmail.com";
        m.From = "info@abc.com";
       
        m.Subject = "Sample Mail";
        m.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", "1");

        //User name on website from where you send a mail.
       m.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusername", "username"   );

       //Password on website from where you send a mail.
       m.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword","password");

        SmtpMail.SmtpServer = "www.abc.com";

        try
        {
            SmtpMail.Send(m);
           Response.Write("Email has been send");
          }
        catch (Exception ex)
        {
            Response.Write(ex.Message);
        }