Windows Service problem 2 - C# Discussion Boards

Do you want to know more?

12-Oct-04 19:15

Hi~

I am writing a program (consist of a main exe and some plugin dll) and hope that I can load the different version of dll .net assmebly. I know that if I upgrade the plugin dll (while the main exe version is remained unchanged) which the version is not the same as the version in compile time will cause exception. However, is there any way to overcome the versioning problem? That means I can successfully load the application (.exe) everytime with the dlls which the version may be changed later.

Thanks

Client - Server

The_Soul_Of_Rock12-Oct-04 18:22

The_Soul_Of_Rock

12-Oct-04 18:22

Please show me how to program an application client - server.
user user server application must be control the client application.
Thank in advanced.

Thanks
Rock Throught The Night

Re: Client - Server

Colin Angus Mackay12-Oct-04 23:56

Colin Angus Mackay

12-Oct-04 23:56

There are lots of different technologies you can use depending on your situation. What are you trying to achieve?

Vogon Building and Loan advise that your planet is at risk if you do not keep up repayments on any mortgage secured upon it. Please remember that the force of gravity can go up as well as down.

Crystal Report Error Message

MMFT12-Oct-04 17:58

MMFT

12-Oct-04 17:58

Hi (Excuse me. My english is very bad.)
I write a C#.Net program and add "Crystal Report" item to my project.(rpt File)
then create "Setup" for it.(Setup.exe , Setup.msi , Setup.ini)
...
When I install my program in another computer,when my program want to use (rpt file)
a message appear in screen:"Can not find KeycodeV2.dll or invalid Keycode". Why?

Please Guide me.

Thanks.

MMFT

Windows Service problem 2

ting66812-Oct-04 17:10

12-Oct-04 17:10

Hi~

I am writting a windows service.

Can I set the properties such as log on identity in my new windows service in program? Then this property can be set automatically after installation of the windows service.

Also, can I write a UI for the windows service to call? For example, in the service solution, add a new project which contains a form. However, when I create a new instance of the form and show it on the service start (i.e inside the onStart() method, there are 2 statements : Form1 f1 = new Form1(); f1.Show(), the form has been shown but the form hang. The controls inside the form cannot be shown and the title of the form show that the form has no response. Is there anything goes wrong?

Matt Philmon12-Oct-04 18:10

12-Oct-04 18:10

1) No, if you mean you want the installutil command to set the user stuff for you, you can't. Installshield, however, CAN do this for you if you write an install. I don't know whether the bundled Installer for VS.NET has this ability or not (but I doubt it).

2) Yes, you can put a form inside your service. However, there are a couple things you need to do. First, once "installed" go to Services, under Administrative Tools under Control Panel. Then go to your service and bring up the properties, go to the second tab and set the "Allow service to interact with desktop" option to enabled. Now, secondly, you OnStart needs to complete in short time. So, the best way to deal with this, is to put in a timer and then in the handler for Elapsed (or Tick or whatever) put in your form. Start the timer in Onstart and stop the timer once in the timer before showing the form. You should be able to continue normally.

ting66812-Oct-04 18:14

12-Oct-04 18:14

Yes
Iam using package written by myself to install the service.
Can I set the property?

Also the form still cannot be shown normally

I set a timer and show the form after 10 sec after the service start.

Is there anything not right?

Matt Philmon12-Oct-04 18:23

12-Oct-04 18:23

I tried a TON of different options myself and found NO WAY of installing a Windows Service automatically with those advanced options set (like user/password, etc.) EXCEPT by writing a full installation package in Installshield Developer. I actually had the company purchase Installshield for this purpose.

ting66812-Oct-04 18:28

12-Oct-04 18:28

ohoh

Also the form still cannot be shown normally

I set a timer and show the form after 10 sec after the service start.

Is there anything not right?

Matt Philmon12-Oct-04 18:49

12-Oct-04 18:49

Dis you set the "Allow service to interact with desktop" in the Properties for your service from within Control Panel/Administrative Services/Services?

Try this: When you create the form, instead of calling Show(), try this:
MyForm.ShowDialog();
MyForm.BringToFront();

ting66813-Oct-04 0:07

13-Oct-04 0:07

Using ShowDialog() is ok
But why using Show() cause no response of the form?

Thanks

context menu

ppp00112-Oct-04 16:16

ppp001

12-Oct-04 16:16

Hi all,

Is it possible for the following implementation ?
In all window applications, when the user select and right click some text
segment in the document window of the application, the context menu will have a menu item that is defined to be certain operation ? e.g like the "copy" operation for some text segment.

Thanks

https server

ppp00112-Oct-04 16:00

ppp001

12-Oct-04 16:00

Hi all,

I originally plan to write a https server from scratch in c# (coz I cannot
use those existing https server like IIS), but I find that the
https protocol itself is pretty complicated. So I may step back to implement some encryption measure on the message carried in the http protocol instead of using https server. And I would like to know are there any better method to have security measure on http transfer than implementing the encrytion measure by myself ?

thanks

Re: https server

Matt Philmon12-Oct-04 18:12

Populating DataGrid with thread

12-Oct-04 18:12

Probably not. HTTPS is definately the best way to go. Barring that, however, you're going to need to write some encryption code. Check out:
http://www.mentalis.org/soft/projects.qpx

GA-BOYZ12-Oct-04 14:52

GA-BOYZ

12-Oct-04 14:52

Hi,

I am trying to populate my datagrid with thread, since the data is quite large, so the user can still do something else while the data being populated in the background.
The data are retreived from SQL database.

So the form will begin populating datagrid when I click on Reload button.
This is what I tried :

<br />
private void btn_reload_Click(object sender, System.EventArgs e)<br />
{<br />
	// Create and run thread to load data<br />
	fthread_parts_daftar = new Thread(new ThreadStart(RefreshGridParts));<br />
	fthread_parts_daftar.Priority = ThreadPriority.Normal;<br />
	fthread_parts_daftar.IsBackground = true;<br />
	fthread_parts_daftar.Start();	<br />
}<br />
<br />
private void RefreshGridParts()<br />
{<br />
	ds_parts.Tables["tabel_parts_daftar"].Clear();<br />
	partsDA.Fill(ds_parts, "tabel_parts_daftar");<br />
	<br />
	grid_partno.Refresh();<br />
<br />
	// Stop thread<br />
	fthread_parts_daftar.Abort();<br />
}<br />

This code gave me the following error :
An unhandled exception of type 'System.NullReferenceException' occurred in system.windows.forms.dll
Additional information: Object reference not set to an instance of an object.

When I removed the thread and just use fill command on the DataAdapter, it worked fine.
So I looked at the threading, and cannot find any mistakes on it.

I am a newbie in C#, and don't have many experience.
Please kindly help me to solve this problem.

Thank you very much in advance.

Re: Populating DataGrid with thread

Vasudevan Deepak Kumar12-Oct-04 23:59

Vasudevan Deepak Kumar

12-Oct-04 23:59

Hi:

I think using a Child Thread to fill Datagrid may not be supported. Instead you can try out JSRS from http://www.ashleyit.com/rs/[^].

Deepak

Deepak Kumar Vasudevan
Personal Web: http://vdeepakkumar.netfirms.com/
I Blog At: http://deepak.blogdrive.com/

Re: Populating DataGrid with thread

GA-BOYZ13-Oct-04 5:08

GA-BOYZ

13-Oct-04 5:08

If child thread cannot fill datagrid, is there someway that I can popup a new window or form saying for the user to wait, while the datagrid is being filled?

Throw Exception - how expensive is it really?

elguaro12-Oct-04 14:51

elguaro

12-Oct-04 14:51

New job, new surprises. This is everywhere in the C# apps here:

MyObject myObject = new MyObject();
if (!myObject.doSomething())
{
LogError(myObject.ErrMsg);
}

doSomething returns false when it encounters an error and saves the error message in the public property ErrMsg, which the caller will use to see the error.

What's wrong with that? Well I must admit I don't really know but it looks wrong to me. Isn't this what exceptions are for:

MyObject myObject = new MyObject();
try{
myObject.doSomething();
}
catch(Exception e){
LogError(e.Message);
}

When I mentioned it I was told throwing exceptions was too expensive. They do have some try/catch blocks but only for exceptions thrown by the .Net framework itself. All application errors are handled with this (at least for me) odd ErrMsg property.

How expensive is it to throw exceptions really? Is it reason enough to come up with a different error handling mechanism? Is it what they are doing such a bad thing that I should push to change it?

Cheers.

Christian Graus12-Oct-04 15:36

Christian Graus

12-Oct-04 15:36

http://blogs.gotdotnet.com/cbrumme/commentview.aspx/d5fbb311-0c95-46ac-9c46-8f8c0e6ae561[^]

Short version, the CLR will always carry the baggage required to allow exceptions, and the cost of Exceptions is only high if they are likely to be thrown frequently inside tight loops. Otherwise, the potential cost of someone deciding they don't need to check the error code somewhere is much higher.

And seeing as you've just started, you should probably read that entire article, and present the most solid case you can, to impress your new employer.

Christian

I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer

elguaro12-Oct-04 17:11

elguaro

12-Oct-04 17:11

Thanks for that Christian. Heavy reading for me, but interesting.

"the potential cost of someone deciding they don't need to check the error code somewhere is much higher"

That's my problem with c#'s unchecked exceptions. You can also forget to catch exceptions (or just be lazy and not do it), just like you could forget to check for error codes. I understood the argument that exceptions are only expensive when you, well, throw them, but I just don't see how unchecked exceptions help in not ignoring errors.

From the article: "It’s relatively easy to forget to check for a returned error code. It’s much harder to inadvertently swallow an exception without handling it".

I don't understand that statement. It might be hard to "inadvertently swallow an exception" but it's way too easy to ignore it (specially when you don't even know what exceptions a method could throw!). And that's just as bad as not checking for error codes ...

I want to present a case in favor of exceptions to my employer but this unchecked exceptions are giving me headaches. As you can guess by now I have a Java background ...

Cheers

Stefan Troschuetz12-Oct-04 20:48

Stefan Troschuetz

12-Oct-04 20:48

elguaro wrote:
"It’s relatively easy to forget to check for a returned error code. It’s much harder to inadvertently swallow an exception without handling it".

I think what's meant here is that forgetting to check an error code is as easy as to forget to catch an exceptions, but both have different consequences. Whereas the unchecked error code just gets lost, the CLR will popup that an unhandled exception occured in your app.
So it's easy to forget the exception handling, but it's much easier to detect it.

www.troschuetz.de