Checks if a TcpClient has been disconnected.

IsClientDisconnected.cs

// Checks if a socket has disconnected
// Adapted from -- http://stackoverflow.com/questions/722240/instantly-detect-client-disconnection-from-server-socket
 private static bool _isDisconnected(TcpClient client)
{
    try
    {
        Socket s = client.Client;
        return s.Poll(10 * 1000, SelectMode.SelectRead) && (s.Available == 0);
    }
    catch(SocketException se)
    {
        // We got a socket error, assume it's disconnected
        return true;
    }
}