nt client = new SmtpClient("smtp.163.com");

client.UseDefaultCredentials = false;

client.Credentials = new System.Net.NetworkCredential("cwy_speed@163.com", "cwy_speed");

client.DeliveryMethod = SmtpDeliveryMethod.Network;

MailAddress addressFrom = new MailAddress("a@a.com", "張三");

MailAddress addressTo = new MailAddress(strto, "李四");

System.Net.Mail.MailMessage message = new MailMessage(addressFrom, addressTo);

message.Sender = new MailAddress("cwy_speed@163.com");

message.BodyEncoding = System.Text.Encoding.UTF8;

message.IsBodyHtml = true;

client.Send(message);

(以上程式碼是可以正確執行的，並且是可以傳送出去的。)