For Gmail:

var client = new SmtpClient("smtp.gmail.com", 587);
client.EnableSsl = true;
client.Credentials = new NetworkCredential("youraccount@gmail.com", "secret");

var mail = new MailMessage();
mail.From = new MailAddress("youraccount@gmail.com");
mail.To.Add("youraccount@gmail.com");
mail.Subject = "Test mail";
mail.Body = "test body";
client.Send(mail);

For Yahoo:

var client = new SmtpClient("smtp.mail.yahoo.com", 587);
client.Credentials = new NetworkCredential("youraccount@yahoo.com", "secret");

var mail = new MailMessage();
mail.From = new MailAddress("youraccount@yahoo.com");
mail.To.Add("destaccount@gmail.com");
mail.Subject = "Test mail";
mail.Body = "test body";
client.Send(mail);            

Bear in mind that some ISPs (including mine) force their clients to use their SMTP server (as a relay). Spamming protection is the reason.

So you should avoid sending e-mail to the Internet from a client application, unless you give user a chance to specify his SMTP hostname or your app relies on the user s e-mail software (MAPI,...).

Imagine how much easier it would be for us to help you, if you posted the complete exception message, along with a stack trace.

Also, go one step farther and enable logging for System.Net.Mail, so we can see any possible failures at the network level.

If you don t know how to enable logging for SNM, here is a link:

http://systemnetmail.com/faq/4.10.aspx

Thanks!

Dave

There are two ways in which We can send the mail,

1)First is using javascript link "mailTo".This will not send the mail automatically but it will just open the mail window.Refer to the below code

   <a class="label" onclick= javascript:buildEmail(this) >Send Mail</a>

Find below the js method

     function buildEmail(el) {
 var emailId = Usermail@gmail.com;
  var subject="Hi";
 var body="Hello";
  el.href = "mailto:" + emailId + "?Subject=" + escape(subject) +
                                            "&Body=" + escape(body);
}

2)The second way is to use System.Net.Mail which will automatically send the mail to the recipients in the secured manner.

    string subject="Hello";
       string body="Data"; 
       using ( MailMessage objMail = new MailMessage ( "Yourmail@gmail.com", "Usermail@gmail.com" ) )//From and To address respectively
                {
                    objMail.IsBodyHtml = false;// Message format is plain text
                    objMail.Priority = MailPriority.High;// Mail Priority = High
                    objMail.Body = "Hello";
                    ArrayList CCarr = new ArrayList();//Assume we add recipients here

                   // populate additional recipients if specified
                    if ( ( CCarr != null ) && ( CCarr .Count > 0 ) )
                    {
                        foreach ( string recipient in CCarr )
                        {
                            if ( recipient != "Please update the email address" )
                            {
                                objMail.CC.Add ( new MailAddress ( recipient ) );
                            }
                        }
                    }

                     // Set the subject of the message - and make sure it is CIS Compliant
                        if ( !subject.StartsWith ( "SigabaSecure:" ) )
                        {
                            subject = "SigabaSecure: " + subject;
                        }   
                  objMail.Subject = subject;

                   // setup credentials for the smpthost
                    string username =  "Username";
                    string passwd =     "xxxxxx";
                    string smtpHost =  "mail.bankofamerica.com";

                    SmtpClient ss = new SmtpClient ();
                    ss.EnableSsl= true;
                    ss.Host = smtpHost;
                    ss.Credentials = new NetworkCredential ( username, passwd );
                    ss.Send ( objMail );
}

Sigaba Secure Email secures e-mail from client to client through the use of desktop plug-ins and Web-based authentication and decryption.