PingCompletedEventHandler 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

PingCompletedEventHandler デリゲート

メモ : このデリゲートは、.NET Framework version 2.0 で新しく追加されたものです。

Ping オブジェクトの PingCompleted イベントを処理するメソッドを表します。

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

Visual Basic (宣言)

Public Delegate Sub PingCompletedEventHandler
 ( _
    sender As Object, _
    e As PingCompletedEventArgs _
)

Visual Basic (使用法)

Dim instance As New PingCompletedEventHandler(AddressOf
 HandlerMethod)

public delegate void PingCompletedEventHandler
 (
    Object sender,
    PingCompletedEventArgs e
)

C++

public delegate void PingCompletedEventHandler
 (
    Object^ sender, 
    PingCompletedEventArgs^ e
)

/** @delegate */
public delegate void PingCompletedEventHandler
 (
    Object sender, 
    PingCompletedEventArgs 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: PingCompleted イベントのソース。

e: イベントデータを格納している PingCompletedEventArgs オブジェクト。

解説

SendAsync 呼び出しで指定されたユーザーデータは、UserState プロパティ内でこのデリゲートによって呼び出されたメソッドで使用されます。

使用例

PingCompletedEventHandler を指定して PingCompleted イベントに応答するコード例を次に示します。

using System;
using System.Text;
using System.Net;
using System.Net.NetworkInformation;
using System.ComponentModel;
using System.Threading;

namespace Examples.System.Net.NetworkInformation.PingTest
{
    public class PingExample
    {
        public static void
 Main (string[] args)
        {
            if (args.Length == 0)
                throw new ArgumentException ("Ping needs
 a host or IP Address.");

            string who = args[0];
            AutoResetEvent waiter = new AutoResetEvent (false);

            Ping pingSender = new Ping ();

            // When the PingCompleted event is raised,
            // the PingCompletedCallback method is called.
            pingSender.PingCompleted += new PingCompletedEventHandler
 (PingCompletedCallback);

            // Create a buffer of 32 bytes of data to be transmitted.
            string data = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
            byte[] buffer = Encoding.ASCII.GetBytes (data);

            // Wait 12 seconds for a reply.
            int timeout = 12000;

            // Set options for transmission:
            // The data can go through 64 gateways or routers
            // before it is destroyed, and the data packet
            // cannot be fragmented.
            PingOptions options = new PingOptions (64, true);

            Console.WriteLine ("Time to live: {0}", options.Ttl);
            Console.WriteLine ("Don't fragment: {0}", options.DontFragment);

            // Send the ping asynchronously.
            // Use the waiter as the user token.
            // When the callback completes, it can wake up this thread.
            pingSender.SendAsync(who, timeout, buffer, options, waiter);

            // Prevent this example application from ending.
            // A real application should do something useful
            // when possible.
            waiter.WaitOne ();
            Console.WriteLine ("Ping example completed.");
        }

        public static void
 PingCompletedCallback (object sender, PingCompletedEventArgs e)
        {
            // If the operation was canceled, display a message to the
 user.
            if (e.Cancelled)
            {
                Console.WriteLine ("Ping canceled.");

                // Let the main thread resume. 
                // UserToken is the AutoResetEvent object that the main
 thread 
                // is waiting for.
                ((AutoResetEvent)e.UserState).Set ();
            }

            // If an error occurred, display the exception to the user.
            if (e.Error != null)
            {
                Console.WriteLine ("Ping failed:");
                Console.WriteLine (e.Error.ToString ());

                // Let the main thread resume. 
                ((AutoResetEvent)e.UserState).Set();
            }

            PingReply reply = e.Reply;

            DisplayReply (reply);

            // Let the main thread resume.
            ((AutoResetEvent)e.UserState).Set();
        }

        public static void
 DisplayReply (PingReply reply)
        {
            if (reply == null)
                return;

            Console.WriteLine ("ping status: {0}", reply.Status);
            if (reply.Status == IPStatus.Success)
            {
                Console.WriteLine ("Address: {0}", reply.Address.ToString
 ());
                Console.WriteLine ("RoundTrip time: {0}", reply.RoundtripTime);
                Console.WriteLine ("Time to live: {0}", reply.Options.Ttl);
                Console.WriteLine ("Don't fragment: {0}", reply.Options.DontFragment);
                Console.WriteLine ("Buffer size: {0}", reply.Buffer.Length);
            }
        }
    }
}