IAsyncResult.AsyncWaitHandle Özellik

Tanım

WaitHandleZaman uyumsuz bir işlemin tamamlanmasını beklemek için kullanılan bir alır.Gets a WaitHandle that is used to wait for an asynchronous operation to complete.

public:
 property System::Threading::WaitHandle ^ AsyncWaitHandle { System::Threading::WaitHandle ^ get(); };
public System.Threading.WaitHandle AsyncWaitHandle { get; }
member this.AsyncWaitHandle : System.Threading.WaitHandle
Public ReadOnly Property AsyncWaitHandle As WaitHandle

Özellik Değeri

WaitHandle

WaitHandleZaman uyumsuz bir işlemin tamamlanmasını beklemek için kullanılan.A WaitHandle that is used to wait for an asynchronous operation to complete.

Örnekler

Aşağıdaki örnek AsyncWaitHandle WaitHandle , bir temsilci üzerinde bir zaman uyumsuz çağrının nasıl bekleneceğini ve nasıl alınacağını gösterir.The following example demonstrates how to use the AsyncWaitHandle property to get a WaitHandle, and how to wait for an asynchronous call on a delegate. , WaitHandle Zaman uyumsuz çağrı tamamlandığında sinyal alırsınız ve yöntemini çağırarak bunu bekleyebilirsiniz WaitOne .The WaitHandle is signaled when the asynchronous call completes, and you can wait for it by calling the WaitOne method.

Örnek iki sınıftan oluşur: zaman uyumsuz olarak çağrılan yöntemi içeren sınıf ve Main çağrıyı yapan yöntemi içeren sınıf.The example consists of two classes: the class that contains the method that is called asynchronously, and the class that contains the Main method that makes the call.

Temsilciler kullanarak yöntemleri zaman uyumsuz olarak çağırma hakkında daha fazla bilgi ve örnek için bkz. zaman uyumsuz yöntemleri zaman uyumsuz olarak çağırma.For more information and more examples of calling methods asynchronously by using delegates, see Calling Synchronous Methods Asynchronously.

using namespace System;
using namespace System::Threading;
using namespace System::Runtime::InteropServices; 

namespace Examples {
namespace AdvancedProgramming {
namespace AsynchronousOperations
{
    public ref class AsyncDemo 
    {
    public:
        // The method to be executed asynchronously.
        String^ TestMethod(int callDuration, [OutAttribute] int% threadId) 
        {
            Console::WriteLine("Test method begins.");
            Thread::Sleep(callDuration);
            threadId = Thread::CurrentThread->ManagedThreadId;
            return String::Format("My call time was {0}.", callDuration);
        }
    };

    // The delegate must have the same signature as the method
    // it will call asynchronously.
    public delegate String^ AsyncMethodCaller(int callDuration, [OutAttribute] int% threadId);
}}}
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);
}
Imports System.Threading
Imports System.Runtime.InteropServices 

Namespace Examples.AdvancedProgramming.AsynchronousOperations
    Public Class AsyncDemo 
        ' The method to be executed asynchronously.
        Public Function TestMethod(ByVal callDuration As Integer, _
                <Out> ByRef threadId As Integer) As String
            Console.WriteLine("Test method begins.")
            Thread.Sleep(callDuration)
            threadId = Thread.CurrentThread.ManagedThreadId()
            return String.Format("My call time was {0}.", callDuration.ToString())
        End Function
    End Class

    ' The delegate must have the same signature as the method
    ' it will call asynchronously.
    Public Delegate Function AsyncMethodCaller(ByVal callDuration As Integer, _
        <Out> ByRef threadId As Integer) As String
End Namespace
#using <TestMethod.dll>

using namespace System;
using namespace System::Threading;
using namespace Examples::AdvancedProgramming::AsynchronousOperations;

void main() 
{
    // The asynchronous method puts the thread id here.
    int threadId;

    // Create an instance of the test class.
    AsyncDemo^ ad = gcnew AsyncDemo();

    // Create the delegate.
    AsyncMethodCaller^ caller = gcnew AsyncMethodCaller(ad, &AsyncDemo::TestMethod);
       
    // Initiate the asychronous call.
    IAsyncResult^ result = caller->BeginInvoke(3000, 
        threadId, nullptr, nullptr);

    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(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.".
 */
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 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.".
 */
Imports System.Threading
Imports System.Runtime.InteropServices 

Namespace Examples.AdvancedProgramming.AsynchronousOperations

    Public Class AsyncMain 
        Shared Sub Main() 
            ' The asynchronous method puts the thread id here.
            Dim threadId As Integer

            ' Create an instance of the test class.
            Dim ad As New AsyncDemo()

            ' Create the delegate.
            Dim caller As New AsyncMethodCaller(AddressOf ad.TestMethod)
       
            ' Initiate the asynchronous call.
            Dim result As IAsyncResult = caller.BeginInvoke(3000, _
                threadId, Nothing, Nothing)

            Thread.Sleep(0)
            Console.WriteLine("Main thread {0} does some work.", _
                Thread.CurrentThread.ManagedThreadId)
            ' Perform additional processing here and then
            ' wait for the WaitHandle to be signaled.
            result.AsyncWaitHandle.WaitOne()

            ' Call EndInvoke to retrieve the results.
            Dim returnValue As String = caller.EndInvoke(threadId, result)

            ' Close the wait handle.
            result.AsyncWaitHandle.Close()

            Console.WriteLine("The call executed on thread {0}, with return value ""{1}"".", _
                threadId, returnValue)
        End Sub
    End Class
End Namespace

'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.".

Açıklamalar

Dönüş değeri, istemcinin işlem tamamlanana kadar yoklama yerine zaman uyumsuz bir işlemin tamamlanmasını beklemesini sağlar IsCompleted .The return value allows the client to wait for an asynchronous operation to complete instead of polling IsCompleted until the operation concludes. Dönüş değeri,, veya işlemi gerçekleştirmek için kullanılabilir WaitOne WaitAny WaitAll .The return value can be used to perform a WaitOne, WaitAny, or WaitAll operation.

Ortak dil çalışma zamanı,, ve gibi bir dizi wasever nesnesi sağlar ManualResetEvent AutoResetEvent ve Mutex bunların tümü Win32 eşitleme temel öğelerini yansıtır.The common language runtime supplies a number of waitable objects, such as ManualResetEvent, AutoResetEvent, and Mutex, all of which mirror Win32 synchronization primitives.

Uygulayanlara Notlar

Uygulayan nesnenin IAsyncResult WaitHandle AsyncWaitHandle özelliği okunana kadar oluşturması gerekmez.The object that implements IAsyncResult does not need to create the WaitHandle until the AsyncWaitHandle property is read. IAsyncResultUygulayıcının seçimi vardır.It is the choice of the IAsyncResult implementer. Ancak uygulayıcının oluşturduğu bir işlem, AsyncWaitHandle WaitHandle uygun zamanda beklemeyi sona ermeyecek olan öğesine işaret eden, uygulayıcının sorumluluğundadır.However, if the implementer creates AsyncWaitHandle, it is the responsibility of the implementer to signal the WaitHandle that will terminate the wait at the appropriate time. Örneğin, AsyncResult zaman uyumsuz olarak çağrılan bir yöntem döndüğünde çağıran adına beklemeyi sonlandırır.For example, AsyncResult terminates the wait on behalf of the caller when an asynchronously invoked method returns. Oluşturulduktan sonra, AsyncWaitHandle Kullanıcı zaman uyumsuz işlemi belirten yöntemi çağırana kadar canlı tutulmalıdır.Once created, AsyncWaitHandle should be kept alive until the user calls the method that concludes the asynchronous operation. Bu sırada nesnenin arkasındaki nesne AsyncWaitHandle atılır.At that time the object behind AsyncWaitHandle can be discarded.

Arayanlara Notlar

İşlemin tamamlanmasını bekleyen istemciler (yoklamaya karşı) bu özelliği, bekleyen bir eşitleme nesnesi almak için kullanın.Clients that wait for the operation to complete (as opposed to polling) use this property to obtain a synchronization object to wait on.


Bir BeginInvoke yöntemi zaman uyumsuz olarak çağırmak ve ortaya çıkan bir bekleme tutamacı elde etmek için bir temsilcinin yöntemini kullandığınızda, IAsyncResult yöntemini çağırarak, bu işlemi kullanmayı bitirdikten hemen sonra bekleme tutamacını kapatmanızı öneririz Close() .When you use the BeginInvoke method of a delegate to call a method asynchronously and obtain a wait handle from the resulting IAsyncResult, we recommend that you close the wait handle as soon as you are finished using it, by calling the Close() method. Yalnızca bekleme tanıtıcısına yapılan tüm başvuruları yayınladıysanız, çöp toplama işlemi geri kazanır, ancak atılabilir nesneleri açıkça kapatıldığında ve çöp toplama daha verimli bir şekilde çalıştığında, sistem kaynakları serbest bırakılır.If you simply release all references to the wait handle, system resources are freed when garbage collection reclaims the wait handle, but garbage collection works more efficiently when disposable objects are explicitly closed or disposed. Daha fazla bilgi için bkz AsyncWaitHandle . özelliği.For more information, see the AsyncWaitHandle property.

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