.NET Remoting Sample - CodeProject

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Introduction

Why am I publishing this sample?

Because it is very difficult to find working code in the MSDN or internet. Most samples require awkward config files or they are much too complicated for beginners. This sample runs immediately and does not require config files.

The original intention was to remote control an application on a slave computer via network. The master sends a command and waits for the slave until it executes the remote command. This sample sends only text strings, but it can easily be expanded to transfer anything. (See class cTransfer.)

Features

Demonstration of .NET Remoting.
Very simple and easy to understand code!!
No awkward config files necessary (Port and Host are specified in the GUI).
Master.exe (client) and Slave.exe (host) can either run on the same computer (localhost) or on different computers in the network.
Multiple Masters can connect to one Slave on the same port (but not at once)
Multiple instances of Masters and Slaves can communicate independently from each other on different ports.
To keep this sample simple, it uses a blocking call to the Slave. This means the Master waits for the response of the Slave. (This may be useful for sending commands to another computer and get the result after the Slave is ready with executing the remote command.)

How does it work?

Programming .NET Remoting

There a three major ways to use .NET Remoting (this sample uses the first one):

Publishing a public object

(Object is created locally and then published.)

Host:

ChannelServices.RegisterChannel (new TcpChannel(1500));
cTransfer Trans = new cTransfer();
RemotingServices.Marshal (Trans, "TestService");

Client:

cTransfer T = (cTransfer) Activator.GetObject(typeof(cTransfer), 
                                 "tcp://host:1500/TestService");

Remote creation of a public object (SAO)

(Object is created on request of client)

Host:

ChannelServices.RegisterChannel (new TcpChannel(1500));
RemotingConfiguration.RegisterWellKnownServiceType(typeof(cTransfer), 
    "TestService", WellKnownObjectMode.Singleton);

Client:

cTransfer T = (cTransfer) Activator.GetObject(typeof(cTransfer), 
                                 "tcp://host:1500/TestService");

Remote creation of a private object (CAO)

(Object is created on host and client receives a reference to it)

Host:

ChannelServices.RegisterChannel (new TcpChannel(1500));
RemotingConfiguration.RegisterActivatedServiceType(typeof(cTransfer));

Client:

object[] attr = {new UrlAttribute("tcp://host:1500")};
object[] args = {"Sample constructor argument"};
cTransfer T = (cTransfer) Activator.CreateInstance(typeof(cTransfer), args, attr);

Notes:

cTransfer is a class which is defined in Remoting.DLL. It contains the variables and an event to communicate between Host and Client.
These samples use port 1500. You can use any TCP port which is unused and not blocked by the firewall.
The Endpoint used here is "TcpService". You can use any name, but Host and Client must always use the same endpoint name!

This should be enough of explanation. Look into the source code: it's really simple!

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Thanks alot..
Srikanth. Vemulapalli

4:32 7 Feb '10

Thanks alot, this is what I am looking for .. Thanks again. Srikanth.Vemulapally
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Having problems Converting it to VB.net
Member 4087942

2:47 19 Dec '09

Is there anyone who is able to convert this excellent sample to VB? Getting an error: Events cannot be declared with a delegate type that has a return type Even after a workaround, having problems to use the "function" Remote.kResponse k_Response = mi_Transfer.CallSlave(k_Action) in vb. Thanks in advance, alex (imavanloon@hotmail.com)
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Good Article but how to compile and run.
rajath8888

2:24 11 Apr '09

I am a beginner to .net remoting. I understood this wonderful article. Can any1 please explain the steps on how to run this code through visual studio?
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Thanks a lot
Bala001

0:06 21 Dec '08

Hi Helmut: Thanks for the wonderful and concise working sample. It works like a charm.
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Re: Thanks a lot
NathanY

1:54 30 Mar '09

Here Here...
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Re: Thanks a lot
Andrew Habegger

9:53 9 Nov '09

Very helpful. Thank you.
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How to make multiple slave available?
Alan88

4:45 30 Jul '07

I think this code just can support 1 master vs 1 slave & multiple master vs slave. Can i have 1 master vs multiple slave? How to do it?
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.Net Remoting
D Nagendra Prasad

20:17 28 Feb '07

"Error sending message to Slave: Cross-thread operation not valid: Control 'textBoxMessage' accessed from a thread other than the thread it was created on." varsha , subham_msc@yahoo.com
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"Cross-thread operation not valid"
Mark1975

18:51 31 Oct '06

When running the app from C# 2005, I click 'send' on the Master, and it gives the error: "Error sending message to Slave: Cross-thread operation not valid: Control 'textBoxMessage' accessed from a thread other than the thread it was created on." Sorry, I currently lack the skills to track down the cause of the problem.
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Re: "Cross-thread operation not valid"
gregmulvihill

14:43 2 Nov '06

In OnMasterEvent (Slave.frmMain), wrap textBoxMessage.Text like this...


this.Invoke((System.Threading.ThreadStart)delegate()
{
	textBoxMessage.Text = string.Format("Message from [{0}]:\r\n{1}\r\n(Click Button \"Send\" to answer)", k_Action.s_Computer, k_Action.s_Command);
});

Master cant receive the message from the client.. why?
kts2005s

12:55 15 Oct '06


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Remoting CAO in .NET 2005
Suranjan Nandi

21:31 19 Jun '06

Hi, I am using COA for remoting coding. My codes are working very fine in .NET 2003, but is going to hang position in .NET 2005. Just after the proxy is created on the client side it is going to hang position. Please suggest.
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Remoting.Dll
attias gabi

6:40 27 Apr '06

Can u post the code for the dll!? thanks
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Re: Remoting.Dll
Elmue

5:00 2 May '06

Häähhh ???? Click on download !
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Thanks
Narayan Ambatipudi

2:52 22 Feb '06

Hi Thanks alot.

I have a doubt.If I create both Server and Client in same windows application and try to open channel for two time then I am getting Channel already opened Exception.But If I split the same logic into different application then its working fine.I know that there is a conflict in same thread.But can u justify this more clearly.

I ll be happy if u can post u r reply to technicalmail@gmail.com.

regards,
Narayan.

VS.Narayan.Ambatipudi

Good Article
Maitreya Kapasi

3:16 22 Apr '05

Hi .... Its really a very good article .. Keep it up
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how can i catter more than one Slave?
supudu

20:00 20 Apr '05

hai there I should say u have provided a pretty good article to begin with but in this one u are stating at this one is only going to work with single Master and Single Slave..... but how to handle when there are more than one single Slave???????? Thanks in Adavance Austin
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Re: how can i catter more than one Slave?
Anonymous

3:03 21 Apr '05

Hello

It depends on what you want to do.

Because this simple sample demonstrates something like "chatting" the slave must block further master calls until the previous call has been answered by a user response.

You can remove this code in the slave:

if (mb_WaitButton)
{
   k_Response.s_Result = "Sorry! Slave is currently busy.\r\nTry again later";
   return k_Response;
}

and also remove:

while (mb_WaitButton)
{
   Thread.Sleep(200);
};

Then you can send text messages from any number of masters and they will be immediately displayed in the slave's edit box.

BUT:
The response will not work properly anymore.
The response of the slave will always be the same. The user will have no chance to enter a text, because the function returns immediately.

So the question is what you want to do ?

If you don't need a response from the slave which requires user interaction, you are ready now. (For example if the slave does a short calculation and sends the resoponse immediately)

But if you need a "real" asynchronous bidirectional communication then put the same listening mechanism also into the master.
You can even let the master and slave listen on the same port if they do not run on the same machine.
Then you don't have a slave and a master anymore. Then both are equal peers.

Then you can do a real chat program.
But I did'nt want to make sample unnecessary complicated.

Helmut

Error while i chage this code to vb.net
Gpawan

6:26 17 Apr '05

Public Delegate Function del_SlaveCall(ByVal k_Action As kAction) As kResponse Public Event ev_SlaveCall As del_SlaveCall But the ERROR says, EVENT CAN'T BE DECLARED WITH A DELEGATE TYPE THAT HAS A RETURN TYPE. CAN YOU LET ME KNOW WHY?
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Re: Error while i chage this code to vb.net
chushumor

3:22 15 Nov '07

Hi, I have the same problem did you resolve this error? Thanks Nachi
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Additional reads
mav.northwind

0:10 7 Apr '05

For all of you who are starting to use .NET Remoting, there's lots of extremely valuable information on the topic to be found on thinktecture[^], written by Ingo Rammer. Practically a must after your first steps on this terrain, especially if you start wondering why some things do not work as expected... :-> Regards, mav
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Re: Additional reads
Anonymous

2:08 7 Apr '05

Hello Interesting article. But 100% theory. 0% code samples So not 100% useful! Ramone
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Re: Additional reads
mav.northwind

2:13 7 Apr '05

True, it's not really newbie-compatible But as soon as one starts dwelling deeper into remoting the infos there are really essential... mav
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