ارسال ایمیل با استفاده از Yahoo!, GMail, Hotmail

Server Parameters

Server Name	SMTP Address	Port	SSL
Yahoo!	smtp.mail.yahoo.com	587	Yes
GMail	smtp.gmail.com	587	Yes
Hotmail	smtp.live.com	587	Yes

Sample Code

using System.Net;
using System.Net.Mail;

string smtpAddress = "smtp.mail.yahoo.com";
int portNumber = 587;
bool enableSSL = true;

string emailFrom = "[e-mail]";
string password = "abcdefg";
string emailTo = "[e-mail]";
string subject = "Hello";
string body = "Hello, I'm just writing this to say Hi!";

using (MailMessage mail = new MailMessage())
    mail.From = new MailAddress(emailFrom);
{
    mail.To.Add(emailTo);
    mail.Subject = subject;
    mail.Body = body;
    mail.IsBodyHtml = true;
    // Can set to false, if you are sending pure text.

    mail.Attachments.Add(new Attachment("C:\\SomeFile.txt"));
    mail.Attachments.Add(new Attachment("C:\\SomeZip.zip"));

    using (SmtpClient smtp = new SmtpClient(smtpAddress, portNumber))
    {
        smtp.Credentials = new NetworkCredential(emailFrom, password);
        smtp.EnableSsl = enableSSL;
}
        smtp.Send(mail);
    }

منبع:

http://www.codeproject.com/Tips/520998/Send-Email-from-Yahoo-GMail-Hotmail-Csharp