1、首先在QQ郵箱當中開啟“POP3/SMTP服務”

.2、獲取“授權碼

剛開始一直使用郵箱的密碼。後面才發現，原來QQ郵箱通過第三方發送郵件應該使用授權碼 o(≧口≦)o

附上騰訊的說明http://service.mail.qq.com/cgi-bin/help?subtype=1&&no=1001256&&id=28

3、編碼

使用SmtpClient來解決

EnableSsl設置為true

UseDefaultCredentials設置為false

Credentials = new System.Net.NetworkCredential("QQ郵箱", "授權碼");

附上代碼，做個備忘

1. public static void Send(Email mail,string email)
2. {
3. SmtpClient client = new SmtpClient("smtp.qq.com");
4. client.EnableSsl = true;
5. client.UseDefaultCredentials = false;
6. client.Credentials = new System.Net.NetworkCredential("QQ郵箱", "授權碼");
8. MailAddress from = new MailAddress("QQ郵箱", "顯示名稱", Encoding.UTF8);//初始化發件人
10. MailAddress to = new MailAddress(email, "", Encoding.UTF8);//初始化收件人
12. //設置郵件內容
13. MailMessage message = new MailMessage(from, to);
14. message.Body = mail.Body;
15. message.BodyEncoding = mail.BodyEncoding;
16. message.Subject = mail.Subject;
17. message.SubjectEncoding = mail.SubjectEncoding;
18. message.IsBodyHtml = mail.IsBodyHtml;
20. //發送郵件
21. try
22. {
23. client.Send(message);
24. }
25. catch (InvalidOperationException iex)
26. { }
27. catch (Exception ex)
28. { }
29. }

註意：一定要先設置 EnableSsl和UseDefaultCredentials，再實例化Credentials

關於QQ郵箱“命令順序不正確。 服務器響應為:Error: need EHLO and AUTH first !”問題