Obtaining info about the mailbox 

To retrieve message count or see of all messages currently in the mailbox, use GetMessageCount or GetMailboxSize methods:

// create POP3 client instance, connect, log in
// ...

// get info about mailbox
int count = client.GetMessageCount();
long size = client.GetMailboxSize();

// print some info
Console.WriteLine("Total mails count: {0}", count);
Console.WriteLine("Total mailbox size: {0}B", size);

' create POP3 client instance, connect, log in
' ...

' get info about mailbox
Dim count As Integer = client.GetMessageCount()
Dim size As Long = client.GetMailboxSize()

' print some info
Console.WriteLine("Total mails count: {0}", count)
Console.WriteLine("Total mailbox size: {0}B", size)

Fine-tuning POP3 behavior 

Pop3 objects makes it possible to specify various low-level settings and workarounds.

Custom commands 

The Pop3 object can execute custom commands, which makes it possible to utilize functionality not yet covered by Rebex API. To send a custom command use the Pop3.SendCommand method. To read the response of this command use the Pop3.ReadResponse method.

POP3 commands either provide a single-line or multi-line response. You need to specify the appropriate mode in the SendCommand method.

The following code sends a single-line STAT and reads its response:

// create POP3 client instance, connect, log in
// ...

// send custom command STAT
client.SendCommand("STAT", false);

// process server response
string response = client.ReadResponse();
Console.WriteLine(response);

' create POP3 client instance, connect, log in
' ...

' send custom command STAT
client.SendCommand("STAT", False)

' process server response
Dim response = client.ReadResponse()
Console.WriteLine(response)

The following code sends a multi-line HELP and reads its response:

// send custom command HELP
client.SendCommand("HELP", true);

// process server response
string response = client.ReadResponse();
while (response != null)
{
    Console.WriteLine(response);
    response = client.ReadResponse();
}

' send custom command HELP
client.SendCommand("HELP", True)

' process server response
Dim response = client.ReadResponse()
While response IsNot Nothing
    Console.WriteLine(response)
    response = client.ReadResponse()
End While