[winform] C# SmtpClient.SendAsync 跟 SmtpClient.Send

mayyola 2020-12-09 13:54:52 ‧ 2344 瀏覽

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大家好:

1.想請問使用gmail sever用SmtpClient.Send會停比較久winform才可以繼續使用
但如果用SmtpClient.SendAsync非同步方式會比較快，但是用outlook收信時，寄件人會變亂碼，想請問什麼方法可以修改嗎?
2.大量寄信的話是一封一封寄，還是多個收件者一次寄比較好呢?

謝謝大家

Mymail = new MailMessage();
Mymail.From = new MailAddress(Senderemail.ToString().Trim(),Sendname.ToString().Trim(),Encoding.UTF8); //寄件者email
Mymail.Subject = textBox4.Text;
Mymail.IsBodyHtml = true; //是否用html格式

foreach (var address in richTextBox1.Text.Split(new[] { ";","," }, StringSplitOptions.RemoveEmptyEntries))
 {
   if (IsValidEmail(address))
 {
 Mymail.To.Add(address);
 }
 }
 SmtpServer.SendAsync(Mymail,"寄件中"); //有沒有記件成功好像還要再另寫程式..

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2 個回答

japhenchen

iT邦超人 1 級 ‧ 2020-12-09 16:07:16

最佳解答

SendAsync沒有比較快，只是不會被卡住視窗轉圈圈...

我都這樣做，outlook收到不會有亂碼，除非你的outlook是早期的express或live版，以下範例以SMTP需登錄的狀況


var stuff = HR.employee.Select(p=>p.Quit==null).ToArray().First();//多筆資料請以foreach處理

SmtpClient smtpClient = new SmtpClient();
smtpClient.Host = "mail.abcdefg.com.tw";
smtpClient.UseDefaultCredentials = false;
smtpClient.Credentials = new NetworkCredential("mis", "abc123456");

using (MailMessage message = new MailMessage())
{
    message.From = new MailAddress("mis@abcdefg.com.tw","管理MIS",Encoding.GetEncoding("utf-8"));
    message.Subject = "教育訓練通知";
    message.SubjectEncoding = Encoding.GetEncoding("utf-8");
    message.BodyEncoding  = Encoding.GetEncoding("utf-8");
    message.IsBodyHtml = true ;
    message.Body = $"<p>(如無法使用手機簡訊，可列印本畫面代替)</p><img src='qr.png' />";
    message.BodyEncoding = Encoding.GetEncoding("utf-8");
    string attimg = Environment.CurrentDirectory + @"\qr.png";
    string g = $"http://www.abcdefg.com.tw/event/attend.aspx?g={guid}&u={stuff.memberid}&sid={stuff.idschedule}";
    var pic = generateQR(g); // 郵件內插QRCODE圖片
    pic.Save(attimg);
    Stream astream = Stream.Null;
    System.Net.Mail.Attachment att1 = new Attachment(attimg);
    att1.Name = System.IO.Path.GetFileName(attimg);
    att1.NameEncoding = Encoding.GetEncoding("utf-8");
    att1.TransferEncoding = System.Net.Mime.TransferEncoding.Base64;
    att1.ContentDisposition.Inline = true;
    att1.ContentDisposition.DispositionType = System.Net.Mime.DispositionTypeNames.Inline;
    message.Attachments.Add(att1);
    message.To.Add(new MailAddress( stuff.mailaddress,stuff.empCName,Encoding.GetEncoding("utf-8")));

    smtpClient.Send(message);
}

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mayyola iT邦研究生 1 級 ‧ 2020-12-09 17:58:50 檢舉

謝謝j大
smtpClient.Send 寄件人不會亂碼，但SmtpClient.SendAsync
想再請問System.Net.Mail 好像沒辦法走 465 port (implicit port的樣子)只能587
我再參考一下您的程式碼感謝~

japhenchen iT邦超人 1 級 ‧ 2020-12-10 07:47:00 檢舉

試試

 using (var client = new SmtpClient())
{
    client.Credentials = new System.Net.NetworkCredential("username", "password");
    client.Port = 465;
    client.Host = "host";
    client.EnableSsl = true; 

    client.Send(message);
}

不過官方文件說內建的不支援implicit SSL，上述方法可能也不行，那你可能就要動用到System.Web.Mail或NUGET下載 Rebex.Mail 或 SecureBlackbox