AsyncResult.AsyncWaitHandle Özellik

Tanım

WaitHandleWin32 eşitleme tutamaçlarını kapsülleyen bir alır ve çeşitli eşitleme düzenlerinin uygulanmasına izin verir.Gets a WaitHandle that encapsulates Win32 synchronization handles, and allows the implementation of various synchronization schemes.

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

Özellik Değeri

WaitHandle

WaitHandleWin32 eşitleme tutamaçlarını kapsülleyen ve çeşitli eşitleme düzenlerinin uygulanmasına izin veren bir.A WaitHandle that encapsulates Win32 synchronization handles, and allows the implementation of various synchronization schemes.

Uygulamalar

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 which 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

WaitHandleBu yöntem tarafından döndürülen zaman uyumsuz işlem tamamlandığında otomatik olarak sinyal verilir.The WaitHandle returned by this method is automatically signaled when the asynchronous operation has completed.

EndInvokeZaman uyumsuz yöntem çağrısını yapmak için kullanılan temsilciyi çağırdığınızda, bekleme tutamacı otomatik olarak kapanmaz.The wait handle is not closed automatically when you call EndInvoke on the delegate that was used to make the asynchronous method call. Bekleme tanıtıcısına yapılan tüm başvuruları serbest bırakırsanız, çöp toplama geri kazanır bekleme tutamacını, sistem kaynakları serbest bırakılır.If you release all references to the wait handle, system resources are freed when garbage collection reclaims the wait handle. Bekleme tutamacını kullanmayı tamamladıktan hemen sonra sistem kaynaklarını serbest bırakmak için WaitHandle.Close yöntemini çağırın.To free the system resources as soon as you are finished using the wait handle, call the WaitHandle.Close method. Çöp toplama, atılabilir nesneleri açıkça kapatıldığında veya bırakıldığında daha verimli bir şekilde çalışabilir.Garbage collection works more efficiently when disposable objects are explicitly closed or disposed.

Dikkat

WaitHandleÖzelliğinde yer alan, AsyncWaitHandle zaman uyumsuz çağrı tamamlanana kadar geçerli iş parçacığını engellemek için kullanılabilir.The WaitHandle contained in the AsyncWaitHandle property can be used to block the current thread until the asynchronous call is complete. Ancak, WaitHandle AsyncCallback çağrı sırasında belirtilmişse öğesini yoksayar BeginInvoke .However the WaitHandle will ignore the AsyncCallback, if one was specified during the BeginInvoke call. Bu nedenle, AsyncCallback WaitHandle zaman uyumsuz çağrının tamamlanmasına kadar engellemek için kullanılsa bile, uygulamanın yürütülmesi bitmeden önce kapandığı durumlar meydana gelebilir.Therefore, a situation can occur where the application shuts down before the AsyncCallback has finished executing, even if a WaitHandle is used to block until the asynchronous call completion. Böyle bir durumla ilgili bir örnek için, sınıfının örneğine bakın AsyncResult ve Thread.Sleep ifadesini kaldırın.For an example of such a situation, see the example for the AsyncResult class, and remove the Thread.Sleep statement.

Şunlara uygulanır

Ayrıca bkz.