TcpListener: how to stop listening while awaiting AcceptTcpClientAsync()?

Question

I don\'t know how to properly close a TcpListener while an async method await for incoming connections. I found this code on SO, here the code :

public class         


        

Answer 1

I used the following solution when continually listening for new connecting clients:

public async Task ListenAsync(IPEndPoint endPoint, CancellationToken cancellationToken)
{
    TcpListener listener = new TcpListener(endPoint);
    listener.Start();

    // Stop() typically makes AcceptSocketAsync() throw an ObjectDisposedException.
    cancellationToken.Register(() => listener.Stop());

    // Continually listen for new clients connecting.
    try
    {
        while (true)
        {
            cancellationToken.ThrowIfCancellationRequested();
            Socket clientSocket = await listener.AcceptSocketAsync();
        }
    }
    catch (OperationCanceledException) { throw; }
    catch (Exception) { cancellationToken.ThrowIfCancellationRequested(); }
}

• I register a callback to call Stop() on the TcpListener instance when the CancellationToken gets canceled.
• AcceptSocketAsync typically immediately throws an ObjectDisposedException then.
• I catch any Exception other than OperationCanceledException though to throw a "sane" OperationCanceledException to the outer caller.

I'm pretty new to async programming, so excuse me if there's an issue with this approach - I'd be happy to see it pointed out to learn from it!