private static IEnumerator<Int32> PipeServerAsyncEnumerator(AsyncEnumerator ae) {
// Each server object performs asynchronous operation on this pipe
using (var pipe = new NamedPipeServerStream(
"Echo", PipeDirection.InOut, -1, PipeTransmissionMode.Message,
PipeOptions.Asynchronous | PipeOptions.WriteThrough)) {
// Asynchronously accept a client connection
pipe.BeginWaitForConnection(ae.End(), null);
yield return 1;
// A client connected, let's accept another client
var aeNewClient = new AsyncEnumerator();
aeNewClient.BeginExecute(PipeServerAsyncEnumerator(aeNewClient),
aeNewClient.EndExecute);
// Accept the client connection
pipe.EndWaitForConnection(ae.DequeueAsyncResult());
// Asynchronously read a request from the client
Byte[] data = new Byte[1000];
pipe.BeginRead(data, 0, data.Length, ae.End(), null);
yield return 1;
// The client sent us a request, process it
Int32 bytesRead = pipe.EndRead(ae.DequeueAsyncResult());
// Just change to upper case
data = Encoding.UTF8.GetBytes(
Encoding.UTF8.GetString(data, 0, bytesRead).ToUpper().ToCharArray());
// Asynchronously send the response back to the client
pipe.BeginWrite(data, 0, data.Length, ae.End(), null);
yield return 1;
// The response was sent to the client, close our side of the connection
pipe.EndWrite(ae.DequeueAsyncResult());
} // Close happens in a finally block now!
}