(VB.NET) Send Email to Distribution List

Sends the same email to a list of 1000 email addresses in 50 sends where each email has 20 recipients.

Note: Chilkat is not intended nor designed for mass emailing. A solution such as this might be used for a corporate emailing to employees, or an emailing to newsletter subscribers.

Chilkat .NET Downloads Chilkat .NET Assemblies Chilkat for .NET Core Chilkat for Mono

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim mailman As New Chilkat.MailMan
Dim success As Boolean

mailman.SmtpHost = "smtp.mymailserver.com"
mailman.SmtpPort = 465
mailman.SmtpSsl = True
mailman.SmtpUsername = "myUsername"
mailman.SmtpPassword = "myPassword"

' Create a new email object
Dim email As New Chilkat.Email
email.Subject = "This is a test"
email.Body = "This is a test"
email.From = "Senders Name <sender@example.com>"
email.AddTo("Subscribers","subscribers@example.com")

Dim bdMime As New Chilkat.BinData
mailman.RenderToMimeBd(email,bdMime)

' Load a file containing one email address per line.
Dim distList As New Chilkat.StringTable
success = distList.AppendFromFile(1000,"utf-8","qa_data/distList.txt")
If (success = False) Then
    Debug.WriteLine(distList.LastErrorText)
    Exit Sub
End If


Dim sbRecipients As New Chilkat.StringBuilder

Dim i As Integer = 0
Dim szDistList As Integer = distList.Count
Dim j As Integer = 0
While i < szDistList

    ' Build a list of comma-separated recipients.
    If (j > 0) Then
        sbRecipients.Append(",")
    End If

    sbRecipients.Append(distList.StringAt(i))

    i = i + 1
    j = j + 1

    ' If we have 20 recipients, or we have the final recipient in the final chunk, then send.
    If ((j = 20) Or (i = szDistList)) Then
        success = mailman.SendMimeBd("sender@example.com",sbRecipients.GetAsString(),bdMime)
        If (success <> True) Then
            Debug.WriteLine(mailman.LastErrorText)
            Exit Sub
        End If

        j = 0
        sbRecipients.Clear()
    End If

End While


success = mailman.CloseSmtpConnection()
If (success <> True) Then
    Debug.WriteLine("Connection to SMTP server not closed cleanly.")
End If


Debug.WriteLine("Email sent to distirbution list.")