Free-ebooks-library - Bahar Ali Khan

...
void MyCallback (IAsyncResult r)
{
int bytesRead;
try { bytesRead = stream.EndWrite (r); }
catch (Exception ex) { Console.Write (ex.Message); }
Console.Write (bytesRead + " bytes read");
}
we can do this:
var buffer = new byte[1000];
Task readChunk = Task.Factory.FromAsync (
stream.BeginRead, stream.EndRead, buffer, 0, 1000, null);
readChunk.ContinueWith (ant => Console.Write (ant.Result + " bytes read"),
TaskContinuationOptions.NotOnFaulted);
readChunk.ContinueWith (ant => Console.Write (ant.Exception.Message),
TaskContinuationOptions.OnlyOnFaulted);
This doesn’t deliver a huge saving in itself: the real benefit comes when you introduce
continuations with child antecedents. Revisiting our earlier example, suppose that
we refactor ReverseEcho’s Begin method so that it calls Read on a new task. This
liberates Server.Serve from having to create a task itself, but more importantly, it
creates a parent for the FromAsync-created tasks upon which we can attach continuations.
This avoids having to write separate exception-handling blocks or explicit
fault continuations for each child task. Cleanup can also be done easily as another
continuation on the parent:
public class Server
{
public void Serve (IPAddress address, int port)
{
ThreadPool.SetMinThreads (50, 50);
TcpListener listener = new TcpListener (address, port);
listener.Start();
while (true)
{
TcpClient c = listener.AcceptTcpClient();
new ReverseEcho().BeginAsync (c);
}
}
}
class ReverseEcho
{
TcpClient _client;
NetworkStream _stream;
byte[] _data = new byte [5000];
int _bytesRead = 0;
internal void BeginAsync (TcpClient c)
{
_client = c;
Asynchronous Methods and Tasks | 935
Asynchronous
Methods