VB.NET

Check the IMAP Socket Connection

Demonstrates the Chilkat Imap.CheckConnection method, which checks whether the underlying TCP socket is currently connected to the IMAP server. This performs a low-level socket-state check and does not send an IMAP command. This example connects and checks the socket.

Background: CheckConnection sits between the cached IsConnected and a full protocol round trip: it inspects the actual socket without sending an IMAP command, so it can catch a locally-closed socket that the cached flag would miss. It still cannot detect every half-open connection, though — only a real command like Noop that expects a server reply proves the session is genuinely alive end to end.

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Dim success As Boolean = False

'  Demonstrates the Imap.CheckConnection method, which checks whether the underlying TCP
'  socket is currently connected to the IMAP server.  This is a low-level socket-state check
'  and does not send an IMAP command.

Dim imap As New Chilkat.Imap

imap.Ssl = True
imap.Port = 993

success = imap.Connect("imap.example.com")
If (success = False) Then
    Debug.WriteLine(imap.LastErrorText)
    Exit Sub
End If


'  Perform a low-level check of the socket connection state.
Dim stillConnected As Boolean = imap.CheckConnection()
If (stillConnected = True) Then
    Debug.WriteLine("The socket is still connected.")
Else
    Debug.WriteLine("The socket is no longer connected.")
End If


success = imap.Disconnect()
If (success = False) Then
    Debug.WriteLine(imap.LastErrorText)
    Exit Sub
End If