IAsyncResult Rozhraní

Definice

Obor názvů:

System

Sestavení:

System.Runtime.dll

Sestavení:

mscorlib.dll

Sestavení:

netstandard.dll

Představuje stav asynchronní operace.

public interface class IAsyncResult

public interface IAsyncResult

[System.Runtime.InteropServices.ComVisible(true)]
public interface IAsyncResult

type IAsyncResult = interface

[<System.Runtime.InteropServices.ComVisible(true)>]
type IAsyncResult = interface

Public Interface IAsyncResult

Odvozené

System.IdentityModel.AsyncResult

System.IdentityModel.Selectors.SecurityTokenProvider.SecurityTokenAsyncResult

System.Runtime.Remoting.Messaging.AsyncResult

System.Threading.Tasks.Task

System.Transactions.CommittableTransaction

System.Web.Services.Protocols.WebClientAsyncResult

Atributy

ComVisibleAttribute

Příklady

Následující příklad ukazuje, jak použít AsyncWaitHandle vlastnost získat WaitHandlea jak počkat na asynchronní volání delegáta. Signalizují WaitHandle se, když se asynchronní volání dokončí, a můžete na něj počkat voláním WaitOne metody.

Příklad se skládá ze dvou tříd: třídy, která obsahuje metodu, která se volá asynchronně, a třídy, která obsahuje metodu Main , která volání provádí.

Další informace a další příklady volání metod asynchronně pomocí delegátů najdete v tématu Asynchronní volání synchronních metod.

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.".

Poznámky

Rozhraní IAsyncResult je implementováno třídami obsahujícími metody, které mohou pracovat asynchronně. Jedná se o návratový typ metod, které inicialují asynchronní operaci, například FileStream.BeginRead, a předává se metodám, které končí asynchronní operaci, například FileStream.EndRead. IAsyncResult Objekty se také předávají metodám vyvolaným AsyncCallback delegáty při dokončení asynchronní operace.

Objekt, který podporuje IAsyncResult rozhraní, ukládá informace o stavu asynchronní operace a poskytuje synchronizační objekt, který umožňuje signalizovat vlákna po dokončení operace.

Poznámka

Třída AsyncResult je implementace IAsyncResult , která je vrácena metodou BeginInvoke , když použijete delegáta k volání metody asynchronně.

Podrobný popis způsobu IAsyncResult použití rozhraní najdete v tématu Asynchronní volání synchronních metod .

Vlastnosti

AsyncState	Získá uživatelem definovaný objekt, který kvalifikuje nebo obsahuje informace o asynchronní operaci.
AsyncWaitHandle	WaitHandle Získá, který se používá k čekání na dokončení asynchronní operace.
CompletedSynchronously	Získá hodnotu, která označuje, zda asynchronní operace dokončena synchronně.
IsCompleted	Získá hodnotu, která označuje, zda asynchronní operace byla dokončena.