IAsyncResult 介面
表示非同步作業 (Asynchronous Operation) 的狀態。
命名空間： System
組件： mscorlib (在 mscorlib.dll 中)
語法
'宣告
<ComVisibleAttribute(True)> _
Public Interface IAsyncResult
'用途
Dim instance As IAsyncResult
[ComVisibleAttribute(true)]
public interface IAsyncResult
[ComVisibleAttribute(true)]
public interface class IAsyncResult
/** @attribute ComVisibleAttribute(true) */
public interface IAsyncResult
ComVisibleAttribute(true)
public interface IAsyncResult
備註
IAsyncResult 介面由包含可非同步作業的方法的類別所實作。它是啟始非同步作業之方法的傳回型別 (Return Type)，例如 FileStream.BeginRead，而且是結束非同步作業之方法的第三個參數的型別，例如 FileStream.EndRead。IAsyncResult 物件也會傳遞至在非同步作業完成時由 AsyncCallback 委派 (Delegate) 所叫用 (Invoke) 的方法。
支援 IAsyncResult 介面的物件會儲存非同步作業的狀態資訊並提供同步物件 (Synchronization Object)，以便在完成作業時通知執行緒。
如需如何使用 IAsyncResult 介面的詳細描述，請參閱以非同步的方式呼叫同步方法 主題。
範例
下列範例展示使用 IAsyncResult 來取得非同步作業的傳回值。
' Asynchronous Callback method.
Public Shared Sub MyCallback(ar As IAsyncResult)
' Obtains the last parameter of the delegate call.
Dim value As Integer = Convert.ToInt32(ar.AsyncState)
' Obtains return value from the delegate call using EndInvoke.
Dim aResult As AsyncResult = CType(ar, AsyncResult)
Dim temp As SampSyncSqrDelegate = CType(aResult.AsyncDelegate, SampSyncSqrDelegate)
Dim result As Integer = temp.EndInvoke(ar)
Console.Write("Simple.SomeMethod (AsyncCallback): Result of ")
Console.WriteLine("{0} in SampleSynchronized.Square is {1} ", value, result)
End Sub 'MyCallback
// Asynchronous Callback method.
public static void MyCallback(IAsyncResult ar) {
// Obtains the last parameter of the delegate call.
int value = Convert.ToInt32(ar.AsyncState);
// Obtains return value from the delegate call using EndInvoke.
AsyncResult aResult = (AsyncResult)ar;
SampSyncSqrDelegate temp = (SampSyncSqrDelegate)aResult.AsyncDelegate;
int result = temp.EndInvoke(ar);
Console.Write("Simple.SomeMethod (AsyncCallback): Result of ");
Console.WriteLine("{0} in SampleSynchronized.Square is {1} ", value, result);
}
// Asynchronous Callback method.
static void MyCallback( IAsyncResult^ ar )
{
// Obtains the last parameter of the delegate call.
int value = Convert::ToInt32( ar->AsyncState );
// Obtains return value from the delegate call using EndInvoke.
AsyncResult^ aResult = dynamic_cast<AsyncResult^>(ar);
SampSyncSqrDelegate^ temp = static_cast<SampSyncSqrDelegate^>(aResult->AsyncDelegate);
int result = temp->EndInvoke( ar );
Console::Write( "Simple::SomeMethod (AsyncCallback): Result of " );
Console::WriteLine( " {0} in SampleSynchronized::Square is {1} ", value, result );
}
// Asynchronous Callback method.
public static void MyCallback(IAsyncResult ar)
{
// Obtains the last parameter of the delegate call.
SampSyncSqrDelegate sampDelg = (SampSyncSqrDelegate)ar.get_AsyncState();
// Obtains return value from the delegate call using EndInvoke.
AsyncResult aResult = (AsyncResult)ar;
SampSyncSqrDelegate temp =
(SampSyncSqrDelegate)(aResult.get_AsyncDelegate());
int threadId = AppDomain.GetCurrentThreadId();
int result = temp.EndInvoke(ar);
Console.Write("Simple.SomeMethod (AsyncCallback): Result of ");
Console.WriteLine("{0} in SampleSynchronized.Square is {1} ",
(Int32)value, (Int32)result);
} //MyCallback
下列範例展示等待非同步作業完成。
Imports System
Imports System.Threading
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Contexts
Imports System.Runtime.Remoting.Messaging
'
' Context-Bound type with Synchronization Context Attribute
'
<Synchronization()> Public Class SampleSyncronized
Inherits ContextBoundObject
' A method that does some work - returns the square of the given number
Public Function Square(i As Integer) As Integer
Console.Write("SampleSyncronized.Square called. ")
Console.WriteLine("The hash of the current thread is: {0}", Thread.CurrentThread.GetHashCode())
Return i * i
End Function 'Square
End Class 'SampleSyncronized
'
' Async delegate used to call a method with this signature asynchronously
'
Delegate Function SampSyncSqrDelegate(i As Integer) As Integer
'Main sample class
Public Class AsyncResultSample
Public Shared Sub Main()
Dim callParameter As Integer = 0
Dim callResult As Integer = 0
'Create an instance of a context-bound type SampleSynchronized
'Because SampleSynchronized is context-bound, the object sampSyncObj
'is a transparent proxy
Dim sampSyncObj As New SampleSyncronized()
'call the method synchronously
Console.Write("Making a synchronous call on the object. ")
Console.WriteLine("The hash of the current thread is: {0}", Thread.CurrentThread.GetHashCode())
callParameter = 10
callResult = sampSyncObj.Square(callParameter)
Console.WriteLine("Result of calling sampSyncObj.Square with {0} is {1}.", callParameter, callResult)
Console.WriteLine("")
Console.WriteLine("")
'call the method asynchronously
Console.Write("Making an asynchronous call on the object. ")
Console.WriteLine("The hash of the current thread is: {0}", Thread.CurrentThread.GetHashCode())
Dim sampleDelegate As New SampSyncSqrDelegate(AddressOf sampSyncObj.Square)
callParameter = 17
Dim aResult As IAsyncResult = sampleDelegate.BeginInvoke(callParameter, Nothing, Nothing)
'Wait for the call to complete
aResult.AsyncWaitHandle.WaitOne()
callResult = sampleDelegate.EndInvoke(aResult)
Console.WriteLine("Result of calling sampSyncObj.Square with {0} is {1}.", callParameter, callResult)
End Sub 'Main
End Class 'AsyncResultSample
using System;
using System.Threading;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Contexts;
using System.Runtime.Remoting.Messaging;
//
// Context-Bound type with Synchronization Context Attribute
//
[Synchronization()]
public class SampleSyncronized : ContextBoundObject
{
// A method that does some work - returns the square of the given number
public int Square(int i)
{
Console.Write("SampleSyncronized.Square called. ");
Console.WriteLine("The hash of the current thread is: {0}", Thread.CurrentThread.GetHashCode());
return i*i;
}
}
//
// Async delegate used to call a method with this signature asynchronously
//
public delegate int SampSyncSqrDelegate(int i);
//Main sample class
public class AsyncResultSample
{
public static void Main()
{
int callParameter = 0;
int callResult = 0;
//Create an instance of a context-bound type SampleSynchronized
//Because SampleSynchronized is context-bound, the object sampSyncObj
//is a transparent proxy
SampleSyncronized sampSyncObj = new SampleSyncronized();
//call the method synchronously
Console.Write("Making a synchronous call on the object. ");
Console.WriteLine("The hash of the current thread is: {0}", Thread.CurrentThread.GetHashCode());
callParameter = 10;
callResult = sampSyncObj.Square(callParameter);
Console.WriteLine("Result of calling sampSyncObj.Square with {0} is {1}.\n\n", callParameter, callResult);
//call the method asynchronously
Console.Write("Making an asynchronous call on the object. ");
Console.WriteLine("The hash of the current thread is: {0}", Thread.CurrentThread.GetHashCode());
SampSyncSqrDelegate sampleDelegate = new SampSyncSqrDelegate(sampSyncObj.Square);
callParameter = 17;
IAsyncResult aResult = sampleDelegate.BeginInvoke(callParameter, null, null);
//Wait for the call to complete
aResult.AsyncWaitHandle.WaitOne();
callResult = sampleDelegate.EndInvoke(aResult);
Console.WriteLine("Result of calling sampSyncObj.Square with {0} is {1}.", callParameter, callResult);
}
}
using namespace System;
using namespace System::Threading;
using namespace System::Runtime::Remoting;
using namespace System::Runtime::Remoting::Contexts;
using namespace System::Runtime::Remoting::Messaging;
//
// Context-Bound type with Synchronization Context Attribute
//
public ref class SampleSyncronized: public ContextBoundObject
{
public:
// A method that does some work - returns the square of the given number
int Square( int i )
{
Console::Write( "SampleSyncronized::Square called. " );
Console::WriteLine( "The hash of the current thread is: {0}", Thread::CurrentThread->GetHashCode() );
return i * i;
}
};
delegate int SampSyncSqrDelegate( //
// Async delegate used to call a method with this signature asynchronously
//
int i );
//Main sample class
int main()
{
int callParameter = 0;
int callResult = 0;
//Create an instance of a context-bound type SampleSynchronized
//Because SampleSynchronized is context-bound, the Object* sampSyncObj
//is a transparent proxy
SampleSyncronized^ sampSyncObj = gcnew SampleSyncronized;
//call the method synchronously
Console::Write( "Making a synchronous call on the Object*. " );
Console::WriteLine( "The hash of the current thread is: {0}", Thread::CurrentThread->GetHashCode() );
callParameter = 10;
callResult = sampSyncObj->Square( callParameter );
Console::WriteLine( "Result of calling sampSyncObj.Square with {0} is {1}.\n\n", callParameter, callResult );
//call the method asynchronously
Console::Write( "Making an asynchronous call on the Object*. " );
Console::WriteLine( "The hash of the current thread is: {0}", Thread::CurrentThread->GetHashCode() );
SampSyncSqrDelegate^ sampleDelegate = gcnew SampSyncSqrDelegate( sampSyncObj, &SampleSyncronized::Square );
callParameter = 17;
IAsyncResult^ aResult = sampleDelegate->BeginInvoke( callParameter, nullptr, 0 );
//Wait for the call to complete
aResult->AsyncWaitHandle->WaitOne();
callResult = sampleDelegate->EndInvoke( aResult );
Console::WriteLine( "Result of calling sampSyncObj.Square with {0} is {1}.", callParameter, callResult );
}
平台
Windows 98、 Windows 2000 SP4、 Windows CE、 Windows Millennium Edition、 Windows Mobile for Pocket PC、 Windows Mobile for Smartphone、 Windows Server 2003、 Windows XP Media Center Edition、 Windows XP Professional x64 Edition、 Windows XP SP2、 Windows XP Starter Edition
.NET Framework 並不支援各種平台的所有版本。如需支援平台版本的相關資訊，請參閱系統需求一節的內容。
版本資訊
.NET Framework
支援版本：2.0、1.1、1.0
.NET Compact Framework
支援版本：2.0、1.0