ITrackingHandler Interface

Definition

Namespace:

System.Runtime.Remoting.Services

Assembly:

mscorlib.dll

Indicates that the implementing object must be notified of marshaling, unmarshaling, and disconnection of objects and proxies by the remoting infrastructure.

public interface class ITrackingHandler

[System.Runtime.InteropServices.ComVisible(true)]
public interface ITrackingHandler

[<System.Runtime.InteropServices.ComVisible(true)>]
type ITrackingHandler = interface

Public Interface ITrackingHandler

Attributes

ComVisibleAttribute

Examples

The following code example shows how to implement the methods of the ITrackingHandler interface to receive notifications from the remoting infrastructure.

The following code example shows how to implement this interface.

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Services;

// Intercept marshal, unmarshal, and disconnect events for an object.
public class TrackingHandler : ITrackingHandler
{
    // Called when the tracked object is marshaled.

    public void MarshaledObject(Object obj, ObjRef objRef)
    {
        // Notify the user of the marshal event.
        Console.WriteLine("Tracking: An instance of {0} was marshaled.", 
            obj.ToString());

        // Print the channel information.
        if (objRef.ChannelInfo != null)
        {
            // Iterate over ChannelData.
            foreach(object data in objRef.ChannelInfo.ChannelData)
            {
                if (data is ChannelDataStore)
                {
                    // Print the URIs from the ChannelDataStore objects.
                    string[] uris = ((ChannelDataStore)data).ChannelUris;
                    foreach(string uri in uris)
                        Console.WriteLine("ChannelUri: " + uri);
                }
            }
        }

        // Print the envoy information.
        if (objRef.EnvoyInfo != null)
            Console.WriteLine("EnvoyInfo: " + objRef.EnvoyInfo.ToString());

        // Print the type information.
        if (objRef.TypeInfo != null)
        {
            Console.WriteLine("TypeInfo: " + objRef.TypeInfo.ToString());
            Console.WriteLine("TypeName: " + objRef.TypeInfo.TypeName);
        }

        // Print the URI.
        if (objRef.URI != null)
            Console.WriteLine("URI: " + objRef.URI.ToString());
    }

    // Called when the tracked object is unmarshaled.
    public void UnmarshaledObject(Object obj, ObjRef objRef)
    {
        Console.WriteLine("Tracking: An instance of {0} was unmarshaled.", 
            obj.ToString());
    }

    // Called when the tracked object is disconnected.
    public void DisconnectedObject(Object obj)
    {
        Console.WriteLine("Tracking: An instance of {0} was disconnected.", 
            obj.ToString());
    }
}

The following code example shows how to implement this interface on a server.

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;
using System.Runtime.Remoting.Services;

public class Server
{
    public static void Main(string[] args)
    {
        // Register the TCP channel.
        TcpChannel channel = new TcpChannel(1234);
        ChannelServices.RegisterChannel(channel);

        // Register a tracking handler.
        ITrackingHandler handler1 = new TrackingHandler();
        TrackingServices.RegisterTrackingHandler(handler1);

        // Register a second handler.
        ITrackingHandler handler2 = new TrackingHandler();
        TrackingServices.RegisterTrackingHandler(handler2);

        // Get the number of currently registered handlers.
        Console.WriteLine("Registered tracking handlers: " + 
            TrackingServices.RegisteredHandlers.Length);

        // Remove the tracking handler from the registered handlers.
        TrackingServices.UnregisterTrackingHandler(handler2);
        Console.WriteLine("Registered tracking handlers: " + 
            TrackingServices.RegisteredHandlers.Length);

        // Create and marshal an object for remote invocation.
        RemoteService service = new RemoteService();
        ObjRef obj = RemotingServices.Marshal(service, "TcpService");

        // Wait for the user prompt.
        Console.WriteLine("\r\nPress ENTER to unmarshal the object.");
        Console.ReadLine();

        // Unmarshal the object.
        RemotingServices.Unmarshal(obj);

        // Wait for the user prompt.
        Console.WriteLine("Press ENTER to disconnect the object.");
        Console.ReadLine();

        // Disconnect the object.
        RemotingServices.Disconnect(service);
    }
}

The following code example shows how to implement this interface on a client for the server in the preceding code example.

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;

public class Client
{
    public static void Main(string[] args)
    {
        // Register the TCP channel.
        ChannelServices.RegisterChannel(new TcpChannel());

        // Register the client for the remote object.
        WellKnownClientTypeEntry remoteType = new WellKnownClientTypeEntry(
            typeof(RemoteService),"tcp://localhost:1234/TcpService");
        RemotingConfiguration.RegisterWellKnownClientType(remoteType);

        // Create an instance of the remote object.
        RemoteService service = new RemoteService(); 

        // Invoke a method on the remote object.
        service.Hello("world");
        Console.WriteLine("Hello invoked on server.");
    }
}

The following code example shows the remote object that is used by the server and the client.

using System;

// Remote object.
public class RemoteService : MarshalByRefObject
{
    private DateTime startTime;

    public RemoteService()
    {
        // Notify the user that the constructor was invoked.
        Console.WriteLine("Constructor invoked.");
        startTime = DateTime.Now;
    }

    ~RemoteService()
    {
        // Notify the user that the finalizer was invoked.
        TimeSpan elapsedTime = 
            new TimeSpan(DateTime.Now.Ticks - startTime.Ticks);
        Console.WriteLine("Finalizer invoked after " + 
            elapsedTime.ToString() + " seconds.");
    }

    public void Hello(string name)
    {
        // Print a simple message.
        Console.WriteLine("Hello, " + name);
    }
}

Remarks

Every object that is registered with TrackingServices is called by remoting when an object or proxy in the current AppDomain is marshaled, unmarshaled, or disconnected.

Note that only objects can be disconnected. An exception is thrown when disconnect is called on a proxy.

Note

This interface makes a link demand. A SecurityException is thrown if the immediate caller makes the call through a reference to the interface and does not have infrastructure permission. See Link Demands for more information.

Methods

DisconnectedObject(Object)	Notifies the current instance that an object has been disconnected from its proxy.
MarshaledObject(Object, ObjRef)	Notifies the current instance that an object has been marshaled.
UnmarshaledObject(Object, ObjRef)	Notifies the current instance that an object has been unmarshaled.