MessageQueue.EndReceive(IAsyncResult) 方法
定義
重要
部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。
完成指定的非同步接收作業。
public:
System::Messaging::Message ^ EndReceive(IAsyncResult ^ asyncResult);public System.Messaging.Message EndReceive (IAsyncResult asyncResult);member this.EndReceive : IAsyncResult -> System.Messaging.MessagePublic Function EndReceive (asyncResult As IAsyncResult) As Message參數
- asyncResult
- IAsyncResult
IAsyncResult，識別要完成的非同步接收作業，並要從其中擷取最終結果。
傳回
與完成的非同步作業相關的 Message。
例外狀況
asyncResult 參數為 null。
asyncResult 參數的語法無效。
存取訊息佇列方法時發生錯誤。
範例
下列程式代碼範例會鏈結異步要求。 它假設本機電腦上有一個名為 「myQueue」 的佇列。 函 Main 式會開始由例程處理的 MyReceiveCompleted 異步操作。 MyReceiveCompleted 會處理目前的訊息，並開始新的異步接收作業。
#using <system.dll>
#using <system.messaging.dll>
using namespace System;
using namespace System::Messaging;
using namespace System::Threading;
ref class MyNewQueue
{
public:
// Define static class members.
static ManualResetEvent^ signal = gcnew ManualResetEvent( false );
static int count = 0;
// Provides an event handler for the ReceiveCompleted
// event.
static void MyReceiveCompleted( Object^ source, ReceiveCompletedEventArgs^ asyncResult )
{
try
{
// Connect to the queue.
MessageQueue^ mq = dynamic_cast<MessageQueue^>(source);
// End the asynchronous receive operation.
mq->EndReceive( asyncResult->AsyncResult );
count += 1;
if ( count == 10 )
{
signal->Set();
}
// Restart the asynchronous receive operation.
mq->BeginReceive();
}
catch ( MessageQueueException^ )
{
// Handle sources of MessageQueueException.
}
// Handle other exceptions.
return;
}
};
// Provides an entry point into the application.
//
// This example performs asynchronous receive
// operation processing.
int main()
{
// Create an instance of MessageQueue. Set its formatter.
MessageQueue^ myQueue = gcnew MessageQueue( ".\\myQueue" );
array<Type^>^p = gcnew array<Type^>(1);
p[ 0 ] = String::typeid;
myQueue->Formatter = gcnew XmlMessageFormatter( p );
// Add an event handler for the ReceiveCompleted event.
myQueue->ReceiveCompleted += gcnew ReceiveCompletedEventHandler( MyNewQueue::MyReceiveCompleted );
// Begin the asynchronous receive operation.
myQueue->BeginReceive();
MyNewQueue::signal->WaitOne();
// Do other work on the current thread.
return 0;
}
using System;
using System.Messaging;
using System.Threading;
namespace MyProject
{
/// <summary>
/// Provides a container class for the example.
/// </summary>
public class MyNewQueue
{
// Define static class members.
static ManualResetEvent signal = new ManualResetEvent(false);
static int count = 0;
//**************************************************
// Provides an entry point into the application.
//
// This example performs asynchronous receive
// operation processing.
//**************************************************
public static void Main()
{
// Create an instance of MessageQueue. Set its formatter.
MessageQueue myQueue = new MessageQueue(".\\myQueue");
myQueue.Formatter = new XmlMessageFormatter(new Type[]
{typeof(String)});
// Add an event handler for the ReceiveCompleted event.
myQueue.ReceiveCompleted +=
new ReceiveCompletedEventHandler(MyReceiveCompleted);
// Begin the asynchronous receive operation.
myQueue.BeginReceive();
signal.WaitOne();
// Do other work on the current thread.
return;
}
//***************************************************
// Provides an event handler for the ReceiveCompleted
// event.
//***************************************************
private static void MyReceiveCompleted(Object source,
ReceiveCompletedEventArgs asyncResult)
{
try
{
// Connect to the queue.
MessageQueue mq = (MessageQueue)source;
// End the asynchronous receive operation.
Message m = mq.EndReceive(asyncResult.AsyncResult);
count += 1;
if (count == 10)
{
signal.Set();
}
// Restart the asynchronous receive operation.
mq.BeginReceive();
}
catch(MessageQueueException)
{
// Handle sources of MessageQueueException.
}
// Handle other exceptions.
return;
}
}
}
Imports System.Messaging
Imports System.Threading
' Provides a container class for the example.
Public Class MyNewQueue
' Define static class members.
Private Shared signal As New ManualResetEvent(False)
Private Shared count As Integer = 0
' Provides an entry point into the application.
'
' This example performs asynchronous receive
' operation processing.
Public Shared Sub Main()
' Create an instance of MessageQueue. Set its formatter.
Dim myQueue As New MessageQueue(".\myQueue")
myQueue.Formatter = New XmlMessageFormatter(New Type() _
{GetType([String])})
' Add an event handler for the ReceiveCompleted event.
AddHandler myQueue.ReceiveCompleted, AddressOf _
MyReceiveCompleted
' Begin the asynchronous receive operation.
myQueue.BeginReceive()
signal.WaitOne()
' Do other work on the current thread.
Return
End Sub
' Provides an event handler for the ReceiveCompleted
' event.
Private Shared Sub MyReceiveCompleted(ByVal [source] As _
[Object], ByVal asyncResult As ReceiveCompletedEventArgs)
Try
' Connect to the queue.
Dim mq As MessageQueue = CType([source], MessageQueue)
' End the asynchronous receive operation.
Dim m As Message = _
mq.EndReceive(asyncResult.AsyncResult)
count += 1
If count = 10 Then
signal.Set()
End If
' Restart the asynchronous receive operation.
mq.BeginReceive()
Catch
' Handle sources of MessageQueueException.
' Handle other exceptions.
End Try
Return
End Sub
End Class
備註
ReceiveCompleted引發事件時，EndReceive(IAsyncResult)完成呼叫所起始的BeginReceive作業。 若要這樣做， EndReceive(IAsyncResult) 請接收訊息。
BeginReceive 可以指定逾時，這會導致 ReceiveCompleted 在訊息出現在佇列中的訊息之前引發事件。 當逾時發生時，沒有訊息抵達佇列時，後續呼叫 會 EndReceive(IAsyncResult) 擲回例外狀況。
EndReceive(IAsyncResult) 用來讀取 (從佇列中移除) 導致 ReceiveCompleted 引發事件的訊息。
如果您要繼續以異步方式接收訊息，您可以在呼叫 之後再次呼叫 BeginReceiveEndReceive(IAsyncResult)。
下表顯示這個方法是否可在各種工作組模式中使用。
| 工作組模式 | 可用 |
|---|---|
| 本機電腦 | 是 |
| 本機計算機和直接格式名稱 | 是 |
| 遠端電腦 | 否 |
| 遠端電腦和直接格式名稱 | 是 |
