IAsyncResult 介面

定義

命名空間:

System

組件:

netstandard.dll, System.Runtime.dll

來源:

IAsyncResult.cs

代表非同步操作的狀態。

public interface class IAsyncResult

public interface IAsyncResult

type IAsyncResult = interface

Public Interface IAsyncResult

衍生

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

範例

以下範例示範如何利用該 AsyncWaitHandle 屬性取得 WaitHandle，以及如何等待對代理的非同步呼叫。 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。

這個範例包含兩個類別：一個包含非同步呼叫的方法，另一個是包含 Main 呼叫的方法的類別。

欲了解更多使用代理非同步呼叫方法的資訊及範例，請參見 「非同步呼叫同步方法」。

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 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.".

備註

介面 IAsyncResult 由包含可非同步操作的方法類別實作。 它是啟動非同步操作 FileStream.BeginRead的方法的回傳類型，例如 ，並傳遞給結束非同步操作的方法，例如 FileStream.EndRead。 IAsyncResult 當非同步操作完成時，物件也會傳遞給代理所呼叫 AsyncCallback 的方法。

支援介面的 IAsyncResult 物件會儲存非同步操作的狀態資訊，並提供同步物件，讓執行緒在操作完成時能收到訊號。

備註

這個AsyncResult類別是當你用代理非同步呼叫方法時，方法會回傳BeginInvoke的實作IAsyncResult。

關於介面的 IAsyncResult 詳細使用說明，請參閱「 呼叫同步方法非同步 」主題。

屬性

名稱	Description
AsyncState	取得一個使用者定義的物件，該物件包含非同步操作的相關資訊。
AsyncWaitHandle	取得 WaitHandle 一個用來等待非同步操作完成的 。
CompletedSynchronously	會獲得一個表示非同步操作是否同步完成的值。
IsCompleted	會得到一個表示非同步操作是否已完成的值。