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Remoting
Posted Date: 29 May 2008 Resource Type: Code Snippets Category: C# Syntax
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Posted By: Kumar Velu Member Level: Diamond
Rating:  Points: 10
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Create a Remotable Object
A remotable object is nothing more than an object that inherits from MarshalByRefObject. The following sample demonstrates a simple class to expose the omnipresent hello world. This object exposes a single method HelloWorld that will return a string. The only values that can be returned from methods are the classes in the .NET Framework that are serializable such as string and DataSet. In addition, if you need to return a user-defined object then the object needs to be marked as serializable.
Create a new C# class library project. Add a class called SampleObject and put in the following code. Add a reference to System.Runtime.Remoting in the project, otherwise the TcpChannel will not be found. Compile the class to make sure you have everything correct.
using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;
namespace CodeGuru.Remoting
{
///
/// Sample object to demonstrate the use of .NET Remoting.
///
public class SampleObject : MarshalByRefObject
{
///
/// Constructor
///
public SampleObject()
{
}
///
/// Return a hello message
///
/// Hello world message
public string HelloWorld()
{
return "Hello World!";
}
}
}
Create a Server To Expose the Remotable Object
We need to create a server object that will act as a listener to accept remote object requests. For this example we will use the TCP/IP channel. We first create an instance of the channel and then register it for use by clients at a specific port. The service can be registered as WellKnownObjectMode.SingleCall, which results in a new instance of the object for each client, or as WellKnownObjectMode.Singleton, which results in one instance of the object used for all clients.
It is not necessary to create the server listener if you are planning to use IIS. For obvious reasons, IIS only supports the use of the HttpChannel. Create a virtual directory for your application and then put code to register your service in the Application_Start event.
For our example, we'll go ahead and create a server listener in case you don't have IIS. Since the service needs to be bound to an available port, for our example I chose 8080, which is a port that I know to be unused on my computer. You may need to choose a different port depending upon what ports you have available. To see a list of the used ports on your computer open a command prompt and issue the command "netstat --a". It may produce a long listing so make sure the command prompt buffer sizes are set to allow scrolling. Compile the class to make sure you have everything correct.
Create a new C# console application project. Add a class called SampleServer and paste in the following code. Add a reference to System.Runtime.Remoting in the project, otherwise the TcpChannel will not be found. In addition, add a reference to the project containing the SampleObject, otherwise the code will not compile because it won't know how to find a reference to SampleObject.
using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;
namespace CodeGuru.Remoting
{
///
/// Sample server to demonstrate the use of .NET Remoting.
///
public class SampleServer
{
public static int Main(string [] args)
{
// Create an instance of a channel
TcpChannel channel = new TcpChannel(8080);
ChannelServices.RegisterChannel(channel);
// Register as an available service with the name HelloWorld
RemotingConfiguration.RegisterWellKnownServiceType(
typeof(SampleObject),
"HelloWorld",
WellKnownObjectMode.SingleCall );
System.Console.WriteLine("Press the enter key to exit...");
System.Console.ReadLine();
return 0;
}
}
}
Create a Client To Use the Remotable Object
Now that we have our remotable object and a server object to listen for requests, let's create a client to use it. Our client will be very simple. It will connect to the server, create an instance of the object using the server, and then execute the HelloWorld method.
Create a new C# console application project. Add a class called SampleClient and paste in the following code. Add a reference to System.Runtime.Remoting in the project, otherwise the TcpChannel will not be found. In addition, add a reference to the project containing the SampleObject, otherwise the code will not compile because it won't know how to find a reference to SampleObject. Compile the class to make sure you have everything correct.
using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;
namespace CodeGuru.Remoting
{
///
/// Sample client to demonstrate the use of .NET Remoting.
///
public class SampleClient
{
public static int Main(string [] args)
{
// Create a channel for communicating w/ the remote object
// Notice no port is specified on the client
TcpChannel chan = new TcpChannel();
ChannelServices.RegisterChannel(chan);
// Create an instance of the remote object
SampleObject obj = (SampleObject) Activator.GetObject(
typeof(CodeGuru.Remoting.SampleObject),
"tcp://localhost:8080/HelloWorld" );
// Use the object
if( obj.Equals(null) )
{
System.Console.WriteLine("Error: unable to locate server");
}
else
{
Console.WriteLine(obj.HelloWorld());
}
return 0;
}
}
}
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Responses
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| Author: komaladevi 29 May 2008 | Member Level: Gold Points : 2 | it would be nice when you have attached the entire code too
| | Author: Kumar Velu 30 May 2008 | Member Level: Diamond Points : 2 | Thanks for your suggesstion...hope i will reproduce it soon..
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