IAsyncResult IAsyncResult IAsyncResult IAsyncResult Interface

定義

表示非同步作業 (Asynchronous Operation) 的狀態。Represents the status of an asynchronous operation.

public interface class IAsyncResult
[System.Runtime.InteropServices.ComVisible(true)]
public interface IAsyncResult
type IAsyncResult = interface
Public Interface IAsyncResult
衍生
屬性

範例

下列範例示範如何使用AsyncWaitHandle屬性來取得WaitHandle,以及如何在委派上等候的非同步呼叫。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. 非同步呼叫完成時, WaitHandle 會收到信號,且您可以呼叫 WaitOne 方法來等候它。The WaitHandle is signaled when the asynchronous call completes, and you can wait for it by calling the WaitOne method.

此範例包含兩個類別: 包含以非同步方式呼叫的方法和類別,其中包含的類別Main進行呼叫的方法。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.

如需詳細資訊和使用委派來以非同步方式呼叫方法的更多範例,請參閱Calling Synchronous Methods AsynchronouslyFor 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
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
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.".

備註

IAsyncResult包含方法,以非同步方式可以操作的類別會實作介面。The IAsyncResult interface is implemented by classes containing methods that can operate asynchronously. 它會初始化非同步作業,例如方法的傳回型別FileStream.BeginRead,並將它傳遞至方法,結束非同步作業,例如FileStream.EndReadIt is the return type of methods that initiate an asynchronous operation, such as FileStream.BeginRead, and it is passed to methods that conclude an asynchronous operation, such as FileStream.EndRead. IAsyncResult 物件也會傳遞至所叫用方法AsyncCallback委派的非同步作業完成時。IAsyncResult objects are also passed to methods invoked by AsyncCallback delegates when an asynchronous operation completes.

支援的物件IAsyncResult介面儲存非同步作業的狀態資訊,並提供同步處理物件,以便在作業完成時收到訊號的執行緒。An object that supports the IAsyncResult interface stores state information for an asynchronous operation and provides a synchronization object to allow threads to be signaled when the operation completes.

注意

AsyncResult類別是實作IAsyncResult時所傳回BeginInvoke當非同步呼叫方法的情況下,您在使用委派的方法。The AsyncResult class is the implementation of IAsyncResult that is returned by the BeginInvoke method when you use a delegate to call a method asynchronously.

如需詳細的說明,如何IAsyncResult介面時,請參閱 < Calling Synchronous Methods Asynchronously主題。For a detailed description of how the IAsyncResult interface is used, see the Calling Synchronous Methods Asynchronously topic.

屬性

AsyncState AsyncState AsyncState AsyncState

取得使用者定義的物件,這個物件符合或包含非同步作業的相關資訊。Gets a user-defined object that qualifies or contains information about an asynchronous operation.

AsyncWaitHandle AsyncWaitHandle AsyncWaitHandle AsyncWaitHandle

取得 WaitHandle,用來等候非同步作業完成。Gets a WaitHandle that is used to wait for an asynchronous operation to complete.

CompletedSynchronously CompletedSynchronously CompletedSynchronously CompletedSynchronously

取得指出非同步作業是否同步完成的值。Gets a value that indicates whether the asynchronous operation completed synchronously.

IsCompleted IsCompleted IsCompleted IsCompleted

取得指出非同步作業是否已經完成的值。Gets a value that indicates whether the asynchronous operation has completed.

適用於