VB.NET

Get the Size of a POP3 Message by UIDL

Demonstrates the Chilkat MailMan.GetSizeByUidl method, which returns the size, in bytes, of the email on the POP3 server identified by a UIDL. The size includes the full message content, including attachments, and the method returns -1 on error. This example looks up a message's size by its UIDL.

Background: A UIDL ("unique ID listing") is POP3's stable identifier for a message — it stays the same across sessions as long as the message remains in the mailbox. Checking a message's size before downloading lets a client skip or defer very large messages, enforce size limits, or show a progress estimate. You can obtain the available UIDLs from GetMailboxInfoXml or FetchUidls.

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'  Demonstrates the MailMan.GetSizeByUidl method, which returns the size, in bytes, of the
'  email on the POP3 server identified by a UIDL.  The size includes the full message
'  content, including attachments.  Returns -1 on error.

Dim mailman As New Chilkat.MailMan

'  Configure the POP3 server connection.
mailman.MailHost = "pop.example.com"
mailman.MailPort = 995
mailman.PopSsl = True
mailman.PopUsername = "user@example.com"
mailman.PopPassword = "myPassword"

'  Get the size of a specific message by its UIDL.
Dim sizeBytes As Integer = mailman.GetSizeByUidl("0000000123abcdef")
Debug.WriteLine("Message size (bytes): " & sizeBytes)

'  Note: Explicitly connecting/authenticating is optional.  Chilkat MailMan automatically
'  connects and authenticates -- using the property settings above -- whenever a server
'  operation requires it.  Calling the explicit connect/authenticate methods can still be
'  helpful to determine whether a failure occurs while connecting or while authenticating.