Send Email with Multiple Threads(Mass Mail) in VB 6.0

In previous section, I introduced how to use asynchronous mode. In this section, I will introduce how to send mass email with multiple threads in VB 6.0.


Visual Basic 6.0 doesn’t support multiple threads. However, FastSender object has an inner threading pool based on MaxThreads count. Firstly, Send method submits email to FastSender mail queue. Secondly threading pool retrieves email from mail queue and sends it out. Finally OnSent event informs that the email was sent successfully or unsuccessfully.

No. of worker threads in the threading pool of FastSender object is automatically adjusted based on the actual usage. The maximum no. of worker threads is up to the value of MaxThread property specified.


Remarks: All of samples in this section are based on first section: Send email in a simple VB 6.0 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 6.0 Example - Send mass email with multiple threads]

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


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

Option Explicit

Const ConnectNormal = 0
Const ConnectSSLAuto = 1
Const ConnectSTARTTLS = 2
Const ConnectDirectSSL = 3
Const ConnectTryTLS = 4

Private WithEvents m_oFastSender As EASendMailObjLib.FastSender
Private oSmtp As EASendMailObjLib.Mail

Private Sub Command1_Click()

    Dim recipientAddr(3) As String
    Dim i As Integer

    If m_oFastSender Is Nothing Or oSmtp Is Nothing Then
        Set m_oFastSender = New EASendMailObjLib.FastSender
        Set oSmtp = New EASendMailObjLib.Mail
        oSmtp.LicenseCode = "TryIt"
        ' Set the maximum no. of worker threads
        m_oFastSender.MaxThreads = 10
    End If

    ' Your sender email address
    oSmtp.FromAddr = ""

    ' Your SMTP server address
    oSmtp.ServerAddr = ""

    ' User and password for ESMTP authentication, if your server doesn't require
    ' User authentication, please remove the following codes.
    oSmtp.UserName = ""
    oSmtp.Password = "testpassword"

    ' ConnectTryTLS means if server supports SSL/TLS connection, SSL/TLS is used automatically
    oSmtp.ConnectType = ConnectTryTLS

    ' If your server uses 587 port
    ' oSmtp.ServerPort = 587

    ' If your server uses 25/587/465 port with SSL/TLS
    ' oSmtp.ConnectType = ConnectSSLAuto
    ' oSmtp.ServerPort = 25 ' 25 or 587 or 465

    recipientAddr(0) = ""
    recipientAddr(1) = ""
    recipientAddr(2) = ""

    For i = 0 To 2
        oSmtp.AddRecipientEx recipientAddr(i), 0
        oSmtp.Subject = "mass email test subject"
        oSmtp.BodyText = "mass email test body sent from vb"
        Call m_oFastSender.Send(oSmtp, i, "any")

End Sub

Private Sub m_oFastSender_OnSent(ByVal lRet As Long, _
                                 ByVal ErrDesc As String, _
                                 ByVal nKey As Long, _
                                 ByVal tParam As String,  _
                                 ByVal Sender As String, _
                                 ByVal Recipients As String)
    If lRet = 0 Then
        MsgBox nKey & " email was sent successfully"
        MsgBox nKey & ": failed to send email: " & ErrDesc
    End If
End Sub

Next Section

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



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