using System;
using System.Threading;
namespace Examples.AdvancedProgramming.AsynchronousOperations
{
public class AsyncDemo
{
// The method to be executed asynchronously.
public string TestMethod(int callDuration, out int threadId)
{
Console.WriteLine("Test method begins.");
Thread.Sleep(callDuration);
threadId = Thread.CurrentThread.ManagedThreadId;
return String.Format("My call time was {0}.", callDuration.ToString());
}
}
// The delegate must have the same signature as the method
// it will call asynchronously.
public delegate string AsyncMethodCaller(int callDuration, out int threadId);
}
namespace Examples.AdvancedProgramming.AsynchronousOperations
{
public class AsyncMain
{
static void Main()
{
// The asynchronous method puts the thread id here.
int threadId;
// Create an instance of the test class.
AsyncDemo ad = new AsyncDemo();
// Create the delegate.
AsyncMethodCaller caller = new AsyncMethodCaller(ad.TestMethod);
// Initiate the asychronous call.
IAsyncResult result = caller.BeginInvoke(3000,
out threadId, null, null);
Thread.Sleep(0);
Console.WriteLine("Main thread {0} does some work.",
Thread.CurrentThread.ManagedThreadId);
// Wait for the WaitHandle to become signaled.
result.AsyncWaitHandle.WaitOne();
// Perform additional processing here.
// Call EndInvoke to retrieve the results.
string returnValue = caller.EndInvoke(out threadId, result);
// Close the wait handle.
result.AsyncWaitHandle.Close();
Console.WriteLine("The call executed on thread {0}, with return value \"{1}\".",
threadId, returnValue);
}
}
}
/* This example produces output similar to the following:
Main thread 1 does some work.
Test method begins.
The call executed on thread 3, with return value "My call time was 3000.".
*/