Pop | 
public override string GetMessageUid( int index, CancellationToken cancellationToken = default )
| Exception | Condition | 
|---|---|
| ArgumentOutOfRangeException | index is not a valid message index. | 
| ObjectDisposedException | The Pop3Client has been disposed. | 
| ServiceNotConnectedException | The Pop3Client is not connected. | 
| ServiceNotAuthenticatedException | The Pop3Client is not authenticated. | 
| NotSupportedException | The POP3 server does not support the UIDL extension. | 
| OperationCanceledException | The operation was canceled via the cancellation token. | 
| IOException | An I/O error occurred. | 
| Pop3CommandException | The POP3 command failed. | 
| Pop3ProtocolException | A POP3 protocol error occurred. | 
Gets the UID of the message at the specified index.
| Not all servers support UIDs, so you should first check the Capabilities property for the UIDL flag or the SupportsUids convenience property. |