(VB.NET) Process Large POP3 Mailbox

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

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

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

Dim mailman As New Chilkat.MailMan

mailman.MailHost = "pop.example.com"

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

mailman.MailPort = 995
mailman.PopSsl = True

' Get the list of UIDLs for all emails in the mailbox.
Dim sa As Chilkat.StringArray = mailman.GetUidls()
If (mailman.LastMethodSuccess = False) Then
    Debug.WriteLine(mailman.LastErrorText)
    Exit Sub
End If


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


Dim chunkSize As Integer = 6

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


Dim saChunk As New Chilkat.StringArray
While (chunkBeginIdx < numEmails)

    Debug.WriteLine(chunkBeginIdx & " to " & chunkEndIdx)

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

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

    ' Download this chunk of email from the POP3 server.
    Dim bundle As Chilkat.EmailBundle = mailman.FetchMultiple(saChunk)
    If (mailman.LastMethodSuccess = False) Then
        Debug.WriteLine(mailman.LastErrorText)
        Exit Sub
    End If


    Debug.WriteLine("Downloaded " & bundle.MessageCount & " emails.")
    Debug.WriteLine("----")

    ' 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


End While