Question

am using system.net.mail to send email as shown below, but its too slow. it takes about a minute to send, whats wrong with my code. Am calling the code below in backgroundworker_dowork.

[edit]: is there a faster alternative, maybe free or open source code

' 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

Leave it up to the SMTP server to distribute the email to the recipients.

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

Use the Bcc property if you don’t want the recipient to see the other names.