Send Email with Multiple Threads(Mass Mail) in VB.NET

In previous section, I introduced how to use asynchronous mode. In this section, I will introduce how to send mass emails with multiple threads in VB.NET.

Introduction

Based on asynchronous mode, you can create multiple SmtpClient instances in your application and send email in multiple threads. Here is a simple sample demonstrates how to use asynchronous mode to send email in multiple threads.

Note

Remarks: All of samples in this section are based on first section: Send email in a simple VB.NET project. To compile and run the following example codes successfully, please click here to learn how to create the test project and add reference of EASendMail to your project.

[VB.NET - Send Mass Emails with Multiple Threads - Example]

The following example codes demonstrate how to send mass email with multiple threads in VB.NET.

Note

To get the full sample projects, please refer to Samples section.

Imports EASendMail 'Add EASendMail namespace
Module Module1
    Sub Main()
       Dim arRcpt() As String = {"test1@adminsystem.com", _
            "test2@adminsystem.com", _
            "test3@adminsystem.com"}
        Dim nRcpt As Integer = arRcpt.Length
        Dim arMail(nRcpt - 1) As SmtpMail
        Dim arSmtp(nRcpt - 1) As SmtpClient
        Dim arResult(nRcpt - 1) As SmtpClientAsyncResult
        For i As Integer = 0 To nRcpt - 1
            arMail(i) = New SmtpMail("TryIt")
            arSmtp(i) = New SmtpClient()
        Next
        For i As Integer = 0 To nRcpt - 1
            Dim oMail As SmtpMail = arMail(i)
            ' Set sender email address
            oMail.From = "sender@emailarchitect.net"

            ' Set recipient email address
            oMail.To = arRcpt(i)

            ' Set email subject
            oMail.Subject = "mass email test from vb.net"

            ' Set email body
            oMail.TextBody = "test from VB, this email is sent to " + arRcpt(i)

            ' Your SMTP server address
            Dim oServer As New SmtpServer("smtp.emailarchitect.net")

            ' User and password for ESMTP authentication, if your server doesn't require
            ' User authentication, please remove the following codes.
            oServer.User = "test@emailarchitect.net"
            oServer.Password = "testpassword"

            ' If your smtp server requires SSL/TLS connection, please add this line
            ' oServer.ConnectType = SmtpConnectType.ConnectSSLAuto

            Dim oSmtp As SmtpClient = arSmtp(i)

            ' Submit email to BeginSendMail method and return
            ' to process another email
            arResult(i) = oSmtp.BeginSendMail(oServer, oMail, Nothing, Nothing)
            Console.WriteLine(String.Format("Start to send email to {0} ...", _
                arRcpt(i)))
        Next

        ' all emails were sent by BeginSendMail Method
        ' now get result by EndSendMail method
        Dim nSent As Integer = 0
        Do While (nSent < nRcpt)
            For i As Integer = 0 To nRcpt - 1
                ' this email is finished
                If (arResult(i) Is Nothing) Then
                    Continue For
                End If
                ' wait for specified email ...
                If (Not arResult(i).AsyncWaitHandle.WaitOne(10, False)) Then
                    Continue For
                End If
                Try
                    ' this email is finished, using EndSendMail to get result
                    arSmtp(i).EndSendMail(arResult(i))
                    Console.WriteLine(String.Format("Send email to {0} successfully", _
                        arRcpt(i)))
                Catch ep As Exception
                    Console.WriteLine( _
                           String.Format("Failed to send email to {0} with error {1}: ", _
                           arRcpt(i), ep.Message))
                End Try
                ' Set this email result to null, then it won't be processed again
                arResult(i) = Nothing
                nSent += 1
            Next
        Loop
    End Sub
End Module

Next Section

At next section I will introduce how to send email using EASendMail Service Queue in ASP.NET/VB.

Appendix

Comments

If you have any comments or questions about above example codes, please click here to add your comments.