(Visual Basic 6.0) Process Large POP3 Mailbox

Demonstrates how to read email from a mailbox that may contain a large number of emails.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

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

Dim mailman As New ChilkatMailMan

mailman.MailHost = "pop.example.com"

mailman.PopUsername = "myLogin"
mailman.PopPassword = "myPassword"

mailman.MailPort = 995
mailman.PopSsl = 1

' Get the list of UIDLs for all emails in the mailbox.
Dim sa As CkStringArray
Set sa = mailman.GetUidls()
If (mailman.LastMethodSuccess = 0) Then
    Debug.Print mailman.LastErrorText
    Exit Sub
End If

Dim i As Long
Dim numEmails As Long
numEmails = sa.Count
If (numEmails = 0) Then
    Debug.Print "Mailbox is empty"
    Exit Sub
End If

Dim chunkSize As Long
chunkSize = 6

' Download the emails in chunks of 6 emails each.
Dim chunkBeginIdx As Long
chunkBeginIdx = 0
Dim chunkEndIdx As Long
chunkEndIdx = chunkSize - 1
If (chunkEndIdx >= numEmails) Then
    chunkEndIdx = numEmails - 1
End If

Dim saChunk As New CkStringArray
Do While (chunkBeginIdx < numEmails)

    Debug.Print chunkBeginIdx & " to " & chunkEndIdx

    ' Build a chunk of UIDLs.
    saChunk.Clear 
    For i = chunkBeginIdx To chunkEndIdx
        success = saChunk.Append(sa.GetString(i))
    Next

    ' Log the UIDLs in this chunk...
    Dim chunkStr As String
    chunkStr = saChunk.SaveToText()
    Debug.Print chunkStr

    ' Download this chunk of email from the POP3 server.
    Dim bundle As ChilkatEmailBundle
    Set bundle = mailman.FetchMultiple(saChunk)
    If (mailman.LastMethodSuccess = 0) Then
        Debug.Print mailman.LastErrorText
        Exit Sub
    End If

    Debug.Print "Downloaded " & bundle.MessageCount & " emails."
    Debug.Print "----"

    ' Process the bundle...
    ' (your application's processing code goes here...)

    ' Get the next chunk...
    chunkBeginIdx = chunkBeginIdx + chunkSize
    chunkEndIdx = chunkEndIdx + chunkSize
    If (chunkEndIdx >= numEmails) Then
        chunkEndIdx = numEmails - 1
    End If

Loop