c#发邮件

  try            {                string _sender = "your_email_address";                string _password = "your_email_password";                SmtpClient client = new SmtpClient("smtp-mail.outlook.com");                client.Port = 25;                client.DeliveryMethod = SmtpDeliveryMethod.Network;                client.UseDefaultCredentials = false;                System.Net.NetworkCredential credentials =                    new System.Net.NetworkCredential(_sender, _password);                client.EnableSsl = true;                client.Credentials = credentials;                MailMessage message = new MailMessage(_sender, "the_receiver_address");                message.Subject = "test";                message.Body = "test";                client.Send(message);                MessageBox.Show("发送成功");            }            catch (Exception ex)            {                MessageBox.Show(ex.Message);            }

发给多个收件人：

string mailto = {"收件人地址1","收件人地址2","收件人地址3"};string[] list = mailto.Split(',');MailMessage message = new MailMessage();message.From = new MailAddress(_sender);foreach(var item in list){    message.To.Add(item);}

之前试的是163邮箱(smtp.163.com)，老是报错:

Mailbox name not allowed. The server response was: authentication is required.

换成outlook邮箱就好了。

参考资料
http://www.cnblogs.com/gb2013/p/3349190.html
http://www.cnblogs.com/akwwl/p/3191713.html
http://www.cnblogs.com/youring2/archive/2008/11/29/1343911.html