how send an email from c# net application

try
            {

                MailMessage mail = new MailMessage();

                SmtpClient SmtpServer = new SmtpClient("smtp.gmail.com");

                mail.From = new MailAddress("userid@gmail.com");

                mail.To.Add(clientmailaddress);

                mail.Subject = "subject";

                mail.Body = "body";



                System.Net.Mail.Attachment attachment;

                attachment = new System.Net.Mail.Attachment("your attachment file");

                mail.Attachments.Add(attachment);



                SmtpServer.Port = 587;

                SmtpServer.Credentials = new System.Net.NetworkCredential("userid@gmail.com", "password");

                SmtpServer.EnableSsl = true;



                SmtpServer.Send(mail);

                MessageBox.Show("mail Send");

            }

            catch (Exception ex)
            {

                MessageBox.Show("mail sending fail");

            }

MailAddress mailfrom = new MailAddress ( "frommail@gmail.com" );
MailAddress mailto = new MailAddress ( "tomail@gmail.com" );
MailMessage newmsg = new MailMessage ( mailfrom, mailto );

newmsg.Subject = "Subject of Email";
newmsg.Body = "Body(message) of email";

////For File Attachment, more file can also be attached

//Attachment att = new Attachment ( "G:\\code.txt" );
//newmsg.Attachments.Add ( att );

SmtpClient smtps = new SmtpClient ( "smtp.gmail.com", 587 );
smtps.UseDefaultCredentials = false;
smtps.Credentials = new NetworkCredential ( "urmail@gmail.com", "urpwd" );
smtps.EnableSsl = true;
smtps.Send ( newmsg );

MailMessage emailmsg = new MailMessage();
        emailmsg.From = new MailAddress("abc@inc.com", "abc");
        emailmsg.To.Add(new MailAddress("cdf@inc.com", "cdf"));
        emailmsg.Subject = "Regarding Some information";
        emailmsg.Body = "stest bodcy";
        emailmsg.IsBodyHtml = true;
        emailmsg.Priority = MailPriority.Normal;
        SmtpClient mailclient = new SmtpClient("smtp.bizmail.yahoo.com");
        mailclient.Credentials = new System.Net.NetworkCredential("careers@inc.com", "123");
                
        mailclient.Send(emailmsg);