PeekCompletedEventHandler デリゲートとは何？わかりやすく解説 Weblio辞書

.NET Framework クラスライブラリリファレンス

索引トップ用語の索引ランキング

PeekCompletedEventHandler デリゲート

MessageQueue の PeekCompleted イベントを処理するメソッドを表します。

名前空間: System.Messaging
アセンブリ: System.Messaging (system.messaging.dll 内)
構文

Visual Basic (宣言)

Public Delegate Sub PeekCompletedEventHandler
 ( _
    sender As Object, _
    e As PeekCompletedEventArgs _
)

Visual Basic (使用法)

Dim instance As New PeekCompletedEventHandler(AddressOf
 HandlerMethod)

public delegate void PeekCompletedEventHandler
 (
    Object sender,
    PeekCompletedEventArgs e
)

C++

public delegate void PeekCompletedEventHandler
 (
    Object^ sender, 
    PeekCompletedEventArgs^ e
)

/** @delegate */
public delegate void PeekCompletedEventHandler
 (
    Object sender, 
    PeekCompletedEventArgs e
)

JScript

JScript では、デリゲートは使用できますが、新規に宣言することはできません。

パラメータ

sender: イベントのソースである MessageQueue。

e: イベントデータを格納している PeekCompletedEventArgs。

解説

PeekCompletedEventHandler デリゲートを作成する場合は、イベントを処理するメソッドを識別してください。イベントをイベントハンドラに関連付けるには、デリゲートのインスタンスをイベントに追加します。デリゲートを削除しない限り、そのイベントが発生すると常にイベントハンドラが呼び出されます。イベントハンドラデリゲートの詳細については、「イベントとデリゲート」を参照してください。

使用例

イベントハンドラ (MyPeekCompleted) のイベントデリゲート (PeekCompletedEventHandler) を作成し、そのデリゲートを MessageQueue.PeekCompleted イベントに関連付ける方法を次の例に示します。このイベントハンドラは、メッセージをピークしてそのラベルを画面に書き込みます。

Visual Basic

Imports System
Imports System.Messaging





' Provides a container class for the example.
Public Class MyNewQueue



        ' Provides an entry point into the application.
        '         
        ' This example performs asynchronous peek 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 PeekCompleted event.
            AddHandler myQueue.PeekCompleted, AddressOf
 _
                MyPeekCompleted

            ' Begin the asynchronous peek operation.
            myQueue.BeginPeek()

            ' Do other work on the current thread.
            Return
        End Sub 'Main


        '**************************************************
        ' Provides an event handler for the PeekCompleted
        ' event.
        '**************************************************

        Private Shared Sub
 MyPeekCompleted(ByVal [source] As _
            [Object], ByVal asyncResult As
 PeekCompletedEventArgs)

            ' Connect to the queue.
            Dim mq As MessageQueue = CType([source],
 MessageQueue)

            ' End the asynchronous peek operation.
            Dim m As Message = mq.EndPeek(asyncResult.AsyncResult)

            ' Display message information on the screen.
            Console.WriteLine(("Message: " + CStr(m.Body)))

            ' Restart the asynchronous peek operation.
            mq.BeginPeek()

            Return

        End Sub 'MyPeekCompleted

End Class 'MyNewQueue

using System;
using System.Messaging;

namespace MyProject
{
    /// <summary>
    /// Provides a container class for the example.
    /// </summary>
    public class MyNewQueue
    {

        //**************************************************
        // Provides an entry point into the application.
        //         
        // This example performs asynchronous peek 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 PeekCompleted event.
            myQueue.PeekCompleted += new 
                PeekCompletedEventHandler(MyPeekCompleted);
            
            // Begin the asynchronous peek operation.
            myQueue.BeginPeek();
            
            // Do other work on the current thread.

            return;
        }


        //**************************************************
        // Provides an event handler for the PeekCompleted
        // event.
        //**************************************************
        
        private static void
 MyPeekCompleted(Object source, 
            PeekCompletedEventArgs asyncResult)
        {
            // Connect to the queue.
            MessageQueue mq = (MessageQueue)source;

            // End the asynchronous peek operation.
            Message m = mq.EndPeek(asyncResult.AsyncResult);

            // Display message information on the screen.
            Console.WriteLine("Message: " + (string)m.Body);

            // Restart the asynchronous peek operation.
            mq.BeginPeek();
            
            return; 
        }
    }
}

C++

#using <system.dll>
#using <system.messaging.dll>

using namespace System;
using namespace System::Messaging;

// This example performs asynchronous peek operation
// processing.
//*************************************************
ref class MyNewQueue
{
public:

   // Provides an event handler for the PeekCompleted
   // event.
   static void MyPeekCompleted( Object^ source,
 PeekCompletedEventArgs^ asyncResult )
   {
      // Connect to the queue.
      MessageQueue^ mq = dynamic_cast<MessageQueue^>(source);

      // End the asynchronous peek operation.
      Message^ m = mq->EndPeek( asyncResult->AsyncResult );

      // Display message information on the screen.
      Console::WriteLine( "Message: {0}", static_cast<String^>(m->Body)
 );

      // Restart the asynchronous peek operation.
      mq->BeginPeek();
      return;
   }
};

// Provides an entry point into the application.
//         
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 PeekCompleted event.
   myQueue->PeekCompleted += gcnew PeekCompletedEventHandler( MyNewQueue::MyPeekCompleted
 );

   // Begin the asynchronous peek operation.
   myQueue->BeginPeek();

   // Do other work on the current thread.
   return 0;
}

package MyProject; 

import System.*;
import System.Messaging.*;

/// <summary>
/// Provides a container class for the example.
/// </summary>
public class MyNewQueue
{
    //**************************************************
    // Provides an entry point into the application.
    //         
    // This example performs asynchronous peek operation
    // processing.
    //**************************************************
    public static void main(String[]
 args)
    {
        // Create an instance of MessageQueue. Set its formatter.
        MessageQueue myQueue = new MessageQueue(".\\myQueue");
        myQueue.set_Formatter(new XmlMessageFormatter(new
 Type[]
            { String.class.ToType() }));
        // Add an event handler for the PeekCompleted event.
        myQueue.add_PeekCompleted(new PeekCompletedEventHandler(MyPeekCompleted));
        // Begin the asynchronous peek operation.
        myQueue.BeginPeek();
        // Do other work on the current thread.
        return;
    } //main

    //**************************************************
    // Provides an event handler for the PeekCompleted
    // event.
    //**************************************************
    private static void
 MyPeekCompleted(Object source,
        PeekCompletedEventArgs asyncResult)
    {
        // Connect to the queue.
        MessageQueue mq = (MessageQueue)source;
        // End the asynchronous peek operation.
        Message m = mq.EndPeek(asyncResult.get_AsyncResult());
        // Display message information on the screen.
        Console.WriteLine("Message: " + (String)(m.get_Body()));
        // Restart the asynchronous peek operation.
        mq.BeginPeek();
        return;
    } //MyPeekCompleted
} //MyNewQueue