C# Discussion Boards - CodeProject

Nathan Tran3-Dec-02 6:07

3-Dec-02 6:07

Hi,

I'm trying to code a chat server that supports tcp/udp connections as well as connections through remoting if the client is behind a firewall. How can I implement the server so that it will support both types of clients? The problem is that remoting requires the server object to be activated by the client but I need the server to be running all the time to support clients that are not using remoting to connect to it.

So the question is, how does an pre-existing object ( instantiated before the activation of the remoting object ) communicate with an object that is activated remotely by a client? The existing object and the activated object are in the same application domain ( I presume ).

This problem has been bugging me for days. I searched the net and there are a whole bunch of remoting tutorials, but none touches on this particular subject. Hopefully, some one here has a clue.

Nathan.

Re: Remoting: Inter object communication.

John Rayner3-Dec-02 8:04

John Rayner

3-Dec-02 8:04

Well, if I understand you correctly you are trying to get your chat server to send a message to the chat client. This message would probably be a new posting to the current discussion. Not having done this before, I'm probably a little out of my depth but here goes anyway ...

Firewalls are obviously going to limit a direct TCP / UDP connection from the server to the client so that option is out. That means that all communication has to be initiated by the chat client. So two options spring to mind:

Have the client poll the server every so often - you don't really get instant chat here and the closer you get to it (i.e. by polling more frequently) the more it clogs up your network and your server.
Have the client initiate an asynchronous request to the server which blocks until the server services it. Then, when a new message comes in to the server it hands the message off to the client. The client sees the response come back and immediately opens another async request.
You'll need a reliable way of identifying individual clients - if you're concerned about firewalls then I don't think IP address will be good enough. Probably each client would need to get an ID from the server and send that along with every request made.

I'd say the second is preferable from a network traffic and immediacy point of view, but it probably won't scale with the number of users (e.g. 5000 users = 5000 connections at the server waiting to be filled). But then who'd want to be in a discussion with 5000 people?!? It will also make the server quite complex to implement as it will have to keep track of which messages have been passed out to which clients. Also, if you have a very active discussion, the client may struggle to keep up - this could be avoided by each client having a number of outstanding requests to the server, but that would further limit the scalability.

Anybody else have any other ideas?

Re: Remoting: Inter object communication.

Nathan Tran3-Dec-02 10:41

Nathan Tran

3-Dec-02 10:41

John,

AFAIK .NET remoting supports serialization of client objects across channel by reference. I am banking on this reference to the client object to maintain a "connection" between server-client. To send a message back to the client I can simply call clientObjectRef.MsgServicingDelegate( Msg ); Indeed this solution will pose a scalability issue since, in affect, the client maintains an open channel with the server. Is this a wise solution? To what extent is the overhead required to maintain an open httpChannel? More importantly, how does the underlying framework acheives this feat?

Nathan.

Re: Remoting: Inter object communication.

John Rayner4-Dec-02 0:33

John Rayner

4-Dec-02 0:33

Well, I wrote a little test app to try what you are suggesting and it didn't work. I got the very long error message "

This remoting proxy has no channel sink which means either the server has no registered server channels that are listening, or this application has no suitable client channel to talk to the server.

". Hats off to MS for at least trying to make their error messages informative ... Wink | ;)

A little digging on the web revealed a sample chapter from a Wrox book (http://www.wrox.com/books/sample-chapters/SampleChapter_186100740x.pdf[^]) which discusses a similar problem. If you look on page 24 of the PDF you'll see that they set the client app with a Remoting channel in order for the server to communicate with the client.

Once I'd modified my test app in this way, everything worked. However, I very much doubt that this will work if there's a firewall in the middle of the connection (which was the problem we were discussing).

Re: Remoting: Inter object communication.

Nathan Tran4-Dec-02 6:59

Nathan Tran

4-Dec-02 6:59

Hi John,

For communicating across a firewall I believe you have to set the HttpChannel on the client side to port 80 or a port that is not blocked. I haven't tried this myself since I'm still coding the message/user handling routines for my chat server. If you have time on your hands could you verify this? Thanks.

Nathan.

Re: Remoting: Inter object communication.

John Rayner4-Dec-02 7:17

John Rayner

4-Dec-02 7:17

It's not the port number that you've got to worry about. It's more the address translation and usual firewall rules base which are going to be issues. Firewalls, in general, don't allow incoming requests to an arbitrary machine protected by them, whatever the port number, unless they have been specifically configured to do so. It's quite usual for them to allow outgoing connections to any server on port 80, but that's a very different thing.

And no, I'm not going to setup a firewall with machines on both sides just so I can test something for you which I don't think will work anyway. Sorry mate, I'm not quite that helpful ...

MonthCalendar

rurko753-Dec-02 5:38

rurko75

3-Dec-02 5:38

Hallo
I have one problem with component MonthCalendar (C#).I need build calendar to my project but set for specific days different background color!!!Can you someone help me?

Robert

Re: MonthCalendar

kaschimer3-Dec-02 10:46

kaschimer

3-Dec-02 10:46

I am assuming ASP.NET here. I had a similar issue, and needed to add in data on certain days.

For the calendar control, there is an event called DayRender which allows you to inspect each day (e.Day) as it is rendered and do something with the cell (e.Cell) (color it, add controls, etc). You can specify a style and then apply the style to the cell that corresponds to the days you want to do something with.

If you have Visual Studio Help available:

ms-help://MS.VSCC/MS.MSDNVS/vbcon/html/vbtskcustomizingindividualdays.htm[^]

Otherwise, you can find it on MSDN:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguidnf/html/cptskcustomizingindividualdays.asp[^]

Hope this helps!

RabidK

Windows Messages

Sean Rock3-Dec-02 3:34

Sean Rock

3-Dec-02 3:34

Hello, I'm looking for any tutorials on windows messages in C#.NET. what i'm trying to do is look at the windows messages sent to any running application.

TIA

Re: Windows Messages

Jeff J3-Dec-02 15:28

Jeff J

3-Dec-02 15:28

You might not find anything like that relating to C#, since there is nothing new about messaging in .Net. Still the same old WndProc() function, and PreProcessMessage() much as in MFC/ATL. Pretty much anything you find for windows messaging in C/C++, will hold true for C# too.

Cheers

Re: Windows Messages

Sean Rock3-Dec-02 22:08

Sean Rock

3-Dec-02 22:08

yeah i kept looking but found nothing specific to c# or .net so have to use wndproc().

cheers.

Converting Texbox.Text to int 32

djkno33-Dec-02 1:28

djkno3

3-Dec-02 1:28

I have a dll I made and have a set property to accept an int. I would like to fill this property by using the textbox class in a form. I call the Convert.ToInt32
like this
property = Convert.ToInt32(TextBox.Text);
now I get a stack overflow in the dll at the

public int property
{
set {property = value;} //This throws the exeption
}

Am I calling everything correctly? Or am I missing somthing?

Re: Converting Texbox.Text to int 32

Rickard Andersson²⁰3-Dec-02 1:47

Rickard Andersson²⁰

3-Dec-02 1:47

djkno3 wrote:
public int property
{
set {property = value;} //This throws the exeption
}

You're assigning the value to the property itself which is wrong.
You'll need a member varible of type int, so change the code to this:

public int MyPropertyName
{
   set{ myMemberInt = value; }
}

Rickard Andersson@Suza Computing
C# and C++ programmer from SWEDEN!
UIN: 50302279
E-Mail: nikado@pc.nu
Speciality: I love C#, ASP.NET and C++!

Re: Converting Texbox.Text to int 32

djkno33-Dec-02 3:09

djkno3

3-Dec-02 3:09

Thanks that was the problem. To get the value do I use the same variable eg return myMemberInt? It works like this but is it the correct way?

Re: Converting Texbox.Text to int 32

kaschimer3-Dec-02 4:01

kaschimer

3-Dec-02 4:01

To create the read/write property you want, you will want to create a get:

<br />
public int MyPropertyName<br />
{   <br />
    set{ myMemberInt = value; }<br />
    get{ return myMemberInt; }<br />
}<br />

RabidK

Re: Converting Texbox.Text to int 32

djkno33-Dec-02 4:50

djkno3

3-Dec-02 4:50

thanks that's what I have I was just wondering if it was correct Big Grin | :-D

or if I was just getting the right answer by chance and have a nice bug pop up later because of it. thanks

Re: Converting Texbox.Text to int 32

Pyt3-Dec-02 1:47

Pyt

3-Dec-02 1:47

It looks like the value entered in the TextBox is too big for an Int32.

MDSN:
The Int32 value type represents signed integers with values ranging from negative 2,147,483,648 through positive 2,147,483,647.

Pyt

Pyt.

Re: Converting Texbox.Text to int 32

djkno33-Dec-02 3:12

djkno3

3-Dec-02 3:12

I guess I should have said that the value was less then the max for an int 32 (eg It was 32) sorry Frown | :(

class diagram

Anonymous3-Dec-02 0:54

Anonymous

3-Dec-02 0:54

i have developed an application in dot net and i want to get its class diagram is there any facility available for that purpose in visual studio dot net ?

Re: class diagram

Ranjan Banerji3-Dec-02 2:09

Ranjan Banerji

3-Dec-02 2:09

I thought, but I could be wrong, that VS .Net came with some version of Visio that would let you do this.

Re: class diagram

Michael P Butler3-Dec-02 3:30

Michael P Butler

3-Dec-02 3:30

If you have the Architect version then you should find a copy of Visio on the installation media. It isn't installed by default. When installed there is an option to Reverse Engineer added to the Project menu.

Michael

Fat bottomed girls
You make the rockin' world go round -- Queen

Re: class diagram

kaschimer3-Dec-02 4:11

kaschimer

3-Dec-02 4:11

There is an add-in project here on CodeProject that might be useful to you if you don't have a copy of VSNET Ent Arch and Visio for Ent Arch.

It's called PocketUML and from what I have seen, it does a pretty fair job:

http://www.codeproject.com/macro/pocketuml.asp[^]

I've downloaded it, but don't really use it much because I have the Ent Arch editions of both.

On a side note, does anyone know if Visio for Ent. Arch. supports full round-trip engineering? Or team collaboration?

RabidK

Request for adv C# tips & tricks

ThaRudeDude2-Dec-02 20:58

ThaRudeDude

2-Dec-02 20:58

Hi all,
Since I have seen some of the greatest C# code on this site; I'd sure appreciate your contribution to a presentation I will be delivering. I'm looking for radical cool C# tips & tricks to demo. You will be mentioned in my presentation, if you do not object. So any cool stuff with unsafe code; com interop; or even general .Net cool tricks are welcome.

You (already) have my eternal gratitude.
Rudi

Re: Request for adv C# tips & tricks

SimonS2-Dec-02 21:39

SimonS

2-Dec-02 21:39

I've given this type of talk a bunch of times since .NET came out and it really depends on the type of audience.

If you use instant messenger then we can chat: simon_stewartDEFINITELYNOTFORSPAM@hotmail.com -- removing capital words. Poke tongue | ;-P

Cheers,
Simon

"From now on, if rogue states want to buy weapons of mass destruction, they're going to have to go on eBay," Mr. Bezos said.

Looping Problem.

Steve McLenithan2-Dec-02 19:59

Steve McLenithan

2-Dec-02 19:59

I have finally found a good use for looping in a small tool I am creating.

maxBits: is defined elsewhere in the code as a maximum integer that cannot be passed.
subs: is also defined elsewhere as an integer that needs to be passed by at least a value of 2.

---------------------------------------
A little more in depth:
IE- (2^x), where "x" is an integer value.
What this is really trying to find is the "x" power of 2's value, that is right after the value of "subs" but that power cannot be higher than "maxBits" and if it is, it is invalid and a message needs to be passed to the user.

Here is my code:
------------------------------------

// newSubs is the value of the "x" power of 2 right after the value of "subs" int newSubs = 0; int n = 0; for (int i = 0; i <= maxBits; i++) {
while (n < subs)
{
newSubs = 2^i;
n = tSubs;
}
}

------------------------------------

It just isn't working and I don’t know why. I have tried many different cominations of looping structures to get the effect I need. With the code given above, the program crashes when a value of 3 is assigned to "subs".

Can anyone help me with the looping structure? I am going insane just thinking about it Wink | ;)

Thanks for the help.
Regards,

********************
* SteveMcLenithan
* <a href="mailto:steve@steve-mac.com">steve@steve-mac.com</a>
* <a href="http://steve-mac.com">http://steve-mac.com</a>
********************

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