Alternative Ways of Reading POP3 Mail

Download Chilkat Email ActiveX

This example describes various ways that email can be read from a POP3 server using the Chilkat email component.

' This example discusses the various ways of reading email from a POP3 server
' using the Chilkat Email Component.
Private Sub Command17_Click()

    Dim mailman As New ChilkatMailMan2
    mailman.UnlockComponent "Anything for 30-day trial"

    ' Set our mail host and login
    mailman.MailHost = "mail.chilkatsoft.com"
    mailman.PopUsername = "****"
    mailman.PopPassword = "****"
    
    ' In no particular order....
    
    ' ------------------------------------
    ' 1: TransferMail
    ' ------------------------------------
    ' Transfer mail downloads all email from the mailbox and removes
    ' each email downloaded from the POP3 server.
    ' We can set limits on the maximum number of emails to download,
    ' or the maximum size so that any emails larger that the max size are skipped
    ' (and remain on the server)
    mailman.MaxCount = 20   ' Don't download more than 20 messages. Emails not downloaded will remain on the server.
    mailman.SizeLimit = 512000  ' Don't download emails greater than 512,000 bytes in size.
    
    Dim bundle As ChilkatEmailBundle2
    Set bundle = mailman.TransferMail()
    If (bundle Is Nothing) Then
        MsgBox mailman.LastErrorText
        Exit Sub
    End If
    
    ' You may iterate over the bundle to do whatever it is your program needs
    ' to do with each email...
    Dim email As ChilkatEmail2
    n = bundle.MessageCount
    For i = 0 To n - 1
        Set email = bundle.GetEmail(i)
        ' ....
    Next
    
    ' ------------------------------------
    ' 2: CopyMail
    ' ------------------------------------
    ' This is the same as TransferMail, except the mail is left on the POP3 server.
    Set bundle = mailman.CopyMail()
    
    ' ------------------------------------
    ' 3: GetAllHeaders and then get selected emails
    ' on demand via GetFullEmail
    ' ------------------------------------
    ' Download the email headers and 1 or more lines of the body.
    ' A bundle of email objects is returned, but each email in the bundle
    ' will lack the full body, and will not have the attachment information
    ' available.  Attachment information is only fully available when the full
    ' email has been downloaded from a POP3 server.  This is a limitation
    ' of the POP3 protocol (not the Chilkat component).  The IMAP protocol is
    ' more feature rich in that headers can be downloaded to include information
    ' about attachments.
    Set bundle = mailman.GetAllHeaders(1)
    ' Your program can display summary information about each email, such as the
    ' From Address, Recipients, Subject, Date Received, etc.  Your program can
    ' download the full email for any given header by calling GetFullEmail.
    ' This example shows how to download the full email for the 1st header in
    ' the bundle.
    Set email = bundle.GetEmail(0)
    Dim fullEmail As ChilkatEmail2
    Set fullEmail = mailman.GetFullEmail(email)
    ' ....
    
    ' ------------------------------------
    ' 4: GetAllHeaders and then get selected emails
    ' on demand via FetchMultiple
    ' ------------------------------------
    ' Another option is to download the full email for a collection of the header-only
    ' emails.  For example, this is how we would download the full emails for all headers
    ' where the From address is "invoiceRequest@mycompany.com"
    Dim uidlArray As New CkStringArray
    ' Download the headers and build a UIDL array for all emails where the FROM address = "invoiceRequest@mycompany.com"
    Set bundle = mailman.GetAllHeaders(1)
    n = bundle.MessageCount
    For i = 0 To n - 1
        Set email = bundle.GetEmail(i)
        If (email.FromAddress = "invoiceRequest@mycompany.com") Then
            uidlArray.Append email.Uidl
        End If
    Next
    
    Dim bundle2 As ChilkatEmailBundle2
    Set bundle2 = mailman.FetchMultiple(uidlArray)
    ' ....
    ' Now we can delete the emails in bundle2 from the POP3 server.
    success = mailman.DeleteBundle(bundle2)
    ' An alternative way of doing it is to delete via the UIDLs:
    success = mailman.DeleteMultiple(uidlArray)
    If (success = 0) Then
        MsgBox mailman.LastErrorText
        Exit Sub
    End If
        
    ' ------------------------------------
    ' 5: GetUidls and then fetch a set of headers
    ' at a time.
    ' ------------------------------------
    ' For very large mailboxes, there may be so many emails that even downloading
    ' headers is too time consuming.  In this case, you can get the complete set
    ' of UIDLs and then download a chunk of headers at a time.
    '
    Set uidlArray = mailman.GetUidls()
    
    ' Perhaps we want the 1st 50 emails...
    maxIdx = 49
    If (uidlArray.Count < 50) Then
        maxIdx = uidlArray.Count - 1
    End If
    
    ' Get a chunk of up to 50 UIDLs
    Dim uidlChunk As New CkStringArray
    If (uidlArray.Count > 0) Then
        For i = 0 To maxIdx
            uidlChunk.Append (uidlArray.GetString(i))
        Next
    End If
    
    ' Download up to 50 headers.
    Set bundle = mailman.FetchMultipleHeaders(uidlChunk, 1)
    ' ....
    
    
End Sub