system.net.mail太慢了

Question

我使用system.net.mail发送电子邮件，如下所示，但它太慢了。发送大概需要一分钟，我的代码出了什么问题。我在backgroundworker_dowork中调用下面的代码。

编辑:有没有更快的替代方案，也许是免费的或者开源的

' send the email '
Dim smtp As SmtpClient = New SmtpClient()
Dim mail As New MailMessage()
Dim i As Long = 0

' SMTP settings  '
With smtp
    .Host = Trim$(sSMTP)
    .Port = Trim$(iPort)
    .UseDefaultCredentials = False
    .Credentials = New System.Net.NetworkCredential(sUserID, sPword)
    .EnableSsl = bSSL
End With

' create the mail '
With mail
    If sAttachment <> vbNullString Then
        .Attachments.Add(New Net.Mail.Attachment(sAttachment))
    End If
    .From = New MailAddress(sFromEmail, sFromName)
    .ReplyTo = New MailAddress(sReplyTo)
    .Subject = sSubject
    .IsBodyHtml = True
    .Body = sMessage
End With

For i = 0 To lstRecipients.Count - 1
    mail.To.Add(lstRecipients(i))
    Debug.Print(lstRecipients(i))
    Try
        smtp.Send(mail)
        lSent += 1
        bwrkMain.ReportProgress(CInt(100 * (i + 1) / iTotalRecipients))
        SetStatus("Sent:" & lstRecipients(i))
    Catch ex As Exception
        bwrkMain.ReportProgress(CInt(100 * (i + 1) / iTotalRecipients))
        SetStatus("Not Sent:" & lstRecipients(i))
    End Try
    mail.To.Clear()
Next

Answer 1

让SMTP服务器将电子邮件分发给收件人。

For i = 0 To lstRecipients.Count - 1
    mail.To.Add(lstRecipients(i))
Next
smtp.Send(mail)

如果不希望收件人看到其他姓名，请使用“密件抄送”属性。

Answer 2

您可能希望切换到“拾取模式”，在该模式下，邮件客户端会将邮件放入本地IIS SMTP发送位置。这样，您就可以异步(某种程度上)发送邮件，尽管您必须对SMTP组件执行install and configure操作。

你的代码在我看来没问题，lag一定在你使用的中继服务器上。