PingCompletedEventHandler 委托

定义

表示将处理 Ping 对象的 PingCompleted 事件的方法。Represents the method that will handle the PingCompleted event of a Ping object.

public delegate void PingCompletedEventHandler(System::Object ^ sender, PingCompletedEventArgs ^ e);
public delegate void PingCompletedEventHandler(object sender, PingCompletedEventArgs e);
type PingCompletedEventHandler = delegate of obj * PingCompletedEventArgs -> unit
Public Delegate Sub PingCompletedEventHandler(sender As Object, e As PingCompletedEventArgs)

参数

sender
Object

PingCompleted 事件源。The source of the PingCompleted event.

e
PingCompletedEventArgs

包含事件数据的 PingCompletedEventArgs 对象。A PingCompletedEventArgs object that contains the event data.

继承
PingCompletedEventHandler

示例

下面的代码示例演示PingCompletedEventHandler如何指定以响应PingCompleted事件。The following code example demonstrates specifying a PingCompletedEventHandler to respond to a PingCompleted event.

#using <System.dll>

using namespace System;
using namespace System::Text;
using namespace System::Net;
using namespace System::Net::NetworkInformation;
using namespace System::ComponentModel;
using namespace System::Threading;
void PingCompletedCallback( Object^ sender, PingCompletedEventArgs^ e );
void DisplayReply( PingReply^ reply );
int main()
{
   array<String^>^args = Environment::GetCommandLineArgs();
   if ( args->Length == 1 )
      throw gcnew ArgumentException( "Ping needs a host or IP Address." );

   String^ who = args[ 1 ];
   AutoResetEvent^ waiter = gcnew AutoResetEvent( false );
   
   Ping ^ pingSender = gcnew Ping;
   
   // When the PingCompleted event is raised,
   // the PingCompletedCallback method is called.
   pingSender->PingCompleted += gcnew PingCompletedEventHandler( PingCompletedCallback );
   
   // Create a buffer of 32 bytes of data to be transmitted.
   String^ data = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
   array<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 = gcnew 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." );
}


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.
      (dynamic_cast<AutoResetEvent^>(e->UserState))->Set();
   }

   
   // If an error occurred, display the exception to the user.
   if ( e->Error != nullptr )
   {
      Console::WriteLine( "Ping failed:" );
      Console::WriteLine( e->Error->ToString() );
      
      // Let the main thread resume. 
      (dynamic_cast<AutoResetEvent^>(e->UserState))->Set();
   }

   PingReply ^ reply = e->Reply;
   DisplayReply( reply );
   
   // Let the main thread resume.
   (dynamic_cast<AutoResetEvent^>(e->UserState))->Set();
}


void DisplayReply( PingReply ^ reply )
{
   if ( reply == nullptr )
      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 );
   }
}

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.");
        }

        private 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);
            }
        }
    }
}

注解

SendAsync调用中指定的用户数据可用于此委托UserState在属性中调用的方法。User data that is specified in a SendAsync call is available to the method invoked by this delegate in the UserState property.

扩展方法

GetMethodInfo(Delegate)

获取指示指定委托表示的方法的对象。Gets an object that represents the method represented by the specified delegate.

适用于