Remoting Question - C# Discussion Boards

Re: File Summary - I tried that already

17-Aug-02 9:53

look up the FileInfo class, i think this does what you need. Smile | :)

Suspicious | :suss: Email: theeclypse@hotmail.com URL: http://www.onyeyiri.co.uk
"All programmers are playwrights and all computers are lousy actors."

Anonymous17-Aug-02 10:03

Anonymous

17-Aug-02 10:03

I have tried that. It has basic information like file creation date but does not allow to access other file information.

Thanks

Re: File Summary

James T. Johnson17-Aug-02 13:20

James T. Johnson

17-Aug-02 13:20

I believe that information is stored somewhere in the JPEG file and that Windows Explorer is reading that information to populate the fields.

James
"And we are all men; apart from the females." - Colin Davies

Remoting Question

stephen woolhead17-Aug-02 8:52

17-Aug-02 8:52

I am writing a simple remoting server and have a little problem.

everytime I restart the server after it has been used by a client I get the following error.

Only one usage of each socket address (protocol/network address/port) is normally permitted

If I leave the machine for about 5 minutes then the problem goes away.

The server code I am using looks like this...

<br />
TcpServerChannel channel = null ;<br />
try<br />
{<br />
   channel = new TcpServerChannel (8088) ;<br />
   ChannelServices.RegisterChannel (channel) ;<br />
   RemotingConfiguration.RegisterWellKnownServiceType (<br />
   typeof (ClassLibrary.Class1), "Hi", WellKnownObjectMode.SingleCall) ;<br />
<br />
   System.Console.WriteLine ("Hit <enter> to exit") ;<br />
   System.Console.ReadLine () ;<br />
}<br />
catch (System.Exception err)<br />
{<br />
   System.Windows.Forms.MessageBox.Show (err.Message) ;<br />
}<br />
finally<br />
{<br />
   if (channel != null)<br />
   {<br />
      ChannelServices.UnregisterChannel (channel) ;<br />
   }<br />
}

As far as I can tell the unregister Channel always gets called.

How do I ensure that the channel is released so it can be reused?

Thanks

Stephen

Sijin18-Aug-02 20:00

Sijin

18-Aug-02 20:00

The channel should get automatically unregistered when you quit the application. Since any port that your process is listening on will be closed when your process terminates.

You say that the problem only occurs after a client has used it, does the problem occur if a client dosen't use it and you restart the server?. If that is the case then the probably lies with the client somehow. Maybe you can post the relevant client code as well.

I had a similar problem once but it was on the Client side, the problem there was that i was showing a messagebox and forgot to close it thus the application never completely terminated and the port remained open.

May the Source be with you
Sonork ID 100.9997 sijinjoseph

stephen woolhead18-Aug-02 22:28

Re: Remoting Question - Really confussed now!!

18-Aug-02 22:28

Thanks for the reply, If I just start and stop the server I have no problems, the server will restart without the error. Its only if a client has connected that the server has a problem.

Both the Client and server are simple c# console apps.

The client code I am using for this test looks like this..

ChannelServices.RegisterChannel (new TcpClientChannel ()) ;<br />
ClassLibrary.Class1 = (ClassLibrary.Class1 )Activator.GetObject (<br />
     typeof (ClassLibrary.Class1), "tcp://localhost:8088/Hi") ;<br />
<br />
for (int i = 0 ; i < 5 ; i++)<br />
{<br />
   Console.WriteLine (hello.Greeting ("Stephen")) ;<br />
}

and the remoted object looks like this

public class Class1: System.MarshalByRefObject<br />
{	<br />
      public string Greeting (string name)<br />
      {<br />
         return "Completed" ;<br />
      }<br />
}

Both the client and the server fully terminate (i.e. debuger returns and nothing in process list) before I attempt to restart the server.

Thanks

Stephen.

stephen woolhead19-Aug-02 1:03

19-Aug-02 1:03

Not having any luck with this problem, so I downloaded TCPView from sysinternals.com.

Now I can see the server program start and open two ports.

The first is different every time and counts up from about 4010 (the lowest I have seen yet) and the port I am intreased in 8088. The clients connect and all is well. I then close the server and I see ports close in TCPView.

I restart the server and I see the ports reopened and attached to the new server process. Then I get the message

Only one usage of each socket address (protocol/network address/port) is normally permitted

WTF, the ports _where_ opened ok?

It fails on this line of code

channel = new TcpServerChannel (8088) ;

This is the stack trace

at System.Runtime.Remoting.Channels.Tcp.TcpServerChannel.StartListening(Object data)
at System.Runtime.Remoting.Channels.Tcp.TcpServerChannel.SetupChannel()
at System.Runtime.Remoting.Channels.Tcp.TcpServerChannel..ctor(Int32 port)
at Server.Server.Main(String[] args) in d:\devwork.net\experimentation\remoting\server\server.cs:line 22

If I sit and watch TCPView for five minutes I do not see any ports closing in that period, but the project works again, only the once, after that delay

So I am at a loss now, Don't really know where to go from here, anyone, any ideas?

Anyone know of any good books or articles on remoting?

Thanks

Stephen

Sijin21-Aug-02 5:54

Sijin

21-Aug-02 5:54

First of all can you also post the server remoting code. Your code seems perfectly allright. Maybe you can use Tracking Services to see what is really going on on the server side. That should be more helpful than using TCPView.

Have you checked Task Manager after closing your server to make sure that it's not running. Your problem is very strange indeed.

May the Source be with you
Sonork ID 100.9997 sijinjoseph

stephen woolhead21-Aug-02 11:46

Launch the Internet Explorer...

21-Aug-02 11:46

I think I have found the cause of the problem.

I have the Winsock Proxy Client installed on this machine that lets me connect to the Internet via an ISA server. If I disable the client the problem goes away. This only seemes to affect servers written in dotnet.

I think I will have a look at the tracking services to see if I can find out more detail on why it is going wrong.

Stephen.

Vortex17-Aug-02 7:00

Vortex

17-Aug-02 7:00

Hi all!

I'm a little bit newbie in c#. I was looking the way to launch a .html file at the Internet Explorer in my application. What i want is to make the possibility to choose a .htm or .html file in a Windows Form, and then launch it with IE....someone can help me? What is the class or property or wharelse that launch applications like IE?

THANx

---
((.)) The Vortex ((.))

Re: Launch the Internet Explorer...

Nnamdi Onyeyiri17-Aug-02 7:06

Re: Launch the Internet Explorer...

17-Aug-02 7:06

here, i wrote this a yesterday - it checks to find out the location of the default browser, then opens the file

using Microsoft.Win32;
using System.Text;
public string GetBrowser()
{
   RegistryKey root = Registry.ClassesRoot;
   RegistryKey regKey = root.OpenSubKey(@"\htmlfile\shell\open\command");
   StringBuilder sb = new StringBuilder((string)regKey.GetValue(String.Empty));
   sb.Remove(0, 1);
   string str = sb.ToString();
   int i = str.IndexOf('"');
   sb.Remove(i, (sb.Length-i));
   return sb.ToString();		
   }

//then to open the borswer with the file.

System.Diagnostics.Process.Start(GetBrowser(), "http://www.codeproject.com");

there ya go

Suspicious | :suss: Email: theeclypse@hotmail.com URL: http://www.onyeyiri.co.uk
"All programmers are playwrights and all computers are lousy actors."

wobble17-Aug-02 7:13

wobble

17-Aug-02 7:13

Nnamdi,

Why don't you just use this:

System.Diagnostics.Process.Start("http://www.sendfakemail.com");

I thought that this would open the default browser anyway.

Can you tell me why you are using the GetBrowser() function?

Thank you for your help.

Regards
Wobble

Re: Launch the Internet Explorer...

Nnamdi Onyeyiri17-Aug-02 7:16

17-Aug-02 7:16

i thought that:

System.Diagnostics.Process.Start("http://www.sendfakemail.com");

would mean IE hijacks it, when that may not be the default browser.

wobble wrote:
an you tell me why you are using the GetBrowser() function?

that is the function i made - shown above, that reads the registry, to find the location of the default browser, by checking what app is set to open .html files.

Suspicious | :suss: Email: theeclypse@hotmail.com URL: http://www.onyeyiri.co.uk
"All programmers are playwrights and all computers are lousy actors."

MySQL databases

Nnamdi Onyeyiri17-Aug-02 6:53

17-Aug-02 6:53

can u access MySql databases with the Sql classes?

Suspicious | :suss: Email: theeclypse@hotmail.com URL: http://www.onyeyiri.co.uk
"All programmers are playwrights and all computers are lousy actors."

Re: MySQL databases

Nathan Blomquist17-Aug-02 7:25

Nathan Blomquist

17-Aug-02 7:25

No, you will need to get ODBC.NET[^] and MyODBC[^]. These will allow you to use similiar classes to the SQL data classes in the data .net framework.

Later,
Nathan

---------------------------
Hmmm... what's a signature?

Re: MySQL databases

Anonymous17-Aug-02 9:32

Anonymous

17-Aug-02 9:32

you can use the mysql# ADO.NET data provider for mysql which can be found at http://mysqlsharp.sourceforge.net

Inheritance question

leppie17-Aug-02 3:33

leppie

17-Aug-02 3:33

Hi all

I have 4 classes. About 80% of there functions are common. So I make an abstract baseclass to inherit from and add any function that is common. The question is how should i declare the functions in the base class and how must i declare the functions that are not applicable in the inherited class. This is what I have come up with.

Option 1:
Abstract class:
protected void Function(){...}
Inherited class:
if needed:
public new Function(){ base.Function() } or
public new Function(){ ...implement...}
if not needed:
do nothing

Option 2:
Abstract class:
public void Function(){...}
Inherited class:
if needed:
do nothing if implementation is not different or
public override void Function(){...implement...}
if not needed:
private new void Function(){} //hide the member

What is the correct / suggested way?

ANy help appreciated Smile | :)

MYrc : A .NET IRC client with C# Plugin Capabilities. See
http://sourceforge.net/projects/myrc for more info. Big Grin | :-D

James T. Johnson17-Aug-02 4:04

James T. Johnson

17-Aug-02 4:04

Rather than straight-out answer your questions I'll offer some suggestions.

Use an abstract base class when the base classes logically follow to inherit from it.

An example is the TextWriter class; it is an abstract class and all of the classes that inherit from it logically follow in the chain (XmlWriter, StreamWriter).

Now I will say that you should re-think the design of your base class if it turns out you have many methods that shouldn't be used by the inheriting classes.

James
"And we are all men; apart from the females." - Colin Davies

leppie17-Aug-02 4:44

leppie

17-Aug-02 4:44

Thanx James

I think it needs some redesign too Frown | :(

How I wish for multiple inheritance...

Cheers

MYrc : A .NET IRC client with C# Plugin Capabilities. See
http://sourceforge.net/projects/myrc for more info. Big Grin | :-D

James T. Johnson17-Aug-02 5:38

James T. Johnson

17-Aug-02 5:38

You could fake it like Eiffel does Smile | :)

given three classes A, B, and C; where A and B are unrelated but C inherits from A and B the Eiffel compiler will do something like this.

interface IA<br />
{<br />
  ... methods, properties, etc of A ...<br />
}<br />
<br />
interface IB <br />
{<br />
  ... methods, properties, etc of C ...<br />
}<br />
<br />
class C : object, IA, IB<br />
{<br />
  private A a;<br />
  private B b;<br />
<br />
  public void MethodOfA()<br />
  {<br />
    a.MethodOfA();<br />
  }<br />
 <br />
  // useful when you specifically request a class in terms of A<br />
  // and B has the same implementation.<br />
  void IA.MethodOfA()<br />
  {<br />
    a.MethodOfA();<br />
  }<br />
 <br />
  ....<br />
}

James
"And we are all men; apart from the females." - Colin Davies