使用异步方式调用同步方法

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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);
}

using System;
using System.Threading;

namespace Examples.AdvancedProgramming.AsynchronousOperations
{
public class AsyncMain
{
public 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);

// Call EndInvoke to wait for the asynchronous call to complete,
// and to retrieve the results.
string returnValue = caller.EndInvoke(out threadId, result);

Console.WriteLine("The call executed on thread {0}, with return value /"{1}/".",
threadId, returnValue);
}
}
}

using System;
using System.Threading;

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 WaitHa
4000
ndle to become signaled.
result.AsyncWaitHandle.WaitOne();

// Perform additional processing here.
// Call EndInvoke to retrieve the results.
string returnValue = caller.EndInvoke(out threadId, result);

Console.WriteLine("The call executed on thread {0}, with return value /"{1}/".",
threadId, returnValue);
}
}
}

using System;
using System.Threading;

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);

// Poll while simulating work.
while(result.IsCompleted == false) {
Thread.Sleep(10);
}

// Call EndInvoke to retrieve the results.
string returnValue = caller.EndInvoke(out threadId, result);

Console.WriteLine("The call executed on thread {0}, with return value /"{1}/".",
threadId, returnValue);
}
}
}

using System;
using System.Threading;

namespace Examples.AdvancedProgramming.AsynchronousOperations
{
public class AsyncMain
{
// Asynchronous method puts the thread id here.
private static int threadId;

static void Main() {
// Create an instance of the test class.
AsyncDemo ad = new AsyncDemo();

// Create the delegate.
AsyncMethodCaller caller = new AsyncMethodCaller(ad.TestMethod);

// Initiate the asychronous call.  Include an AsyncCallback
// delegate representing the callback method, and the data
// needed to call EndInvoke.
IAsyncResult result = caller.BeginInvoke(3000,
out threadId,
new AsyncCallback(CallbackMethod),
caller );

Console.WriteLine("Press Enter to close application.");
Console.ReadLine();
}

// Callback method must have the same signature as the
// AsyncCallback delegate.
static void CallbackMethod(IAsyncResult ar)
{
// Retrieve the delegate.
AsyncMethodCaller caller = (AsyncMethodCaller) ar.AsyncState;

// Call EndInvoke to retrieve the results.
string returnValue = caller.EndInvoke(out threadId, ar);

Console.WriteLine("The call executed on thread {0}, with return value /"{1}/".",
threadId, returnValue);
}
}
}