Design Technique - C# Discussion Boards

Re: How to validate regular expression pattern?

9-Dec-03 5:53

Just create a new instance of the RegEx. If the regex is invalid, an exception is thrown (this is documented in the class constructor information):

try
{
  Regex re = new Regex("/mypattern/");
  Console.WriteLine("The regular expression is valid.");
}
catch
{
  Console.WriteLine("The regular expression is invalid!");
}

If you move the re declaration outside, you can use it if it's valid after the catch (but then the catch should return or something to keep from trying to use the invalid Regex object).

-----BEGIN GEEK CODE BLOCK-----
Version: 3.21
GCS/G/MU d- s: a- C++++ UL@ P++(+++) L+(--) E--- W+++ N++ o+ K? w++++ O- M(+) V? PS-- PE Y++ PGP++ t++@ 5 X+++ R+@ tv+ b(-)>b++ DI++++ D+ G e++>+++ h---* r+++ y+++
-----END GEEK CODE BLOCK-----

gokselm10-Dec-03 11:35

gokselm

10-Dec-03 11:35

Thanks for your help Heath.

Change Notification

mkomasi9-Dec-03 2:50

mkomasi

9-Dec-03 2:50

Hi,

I want to write a program that send a notififcation when files or folders in a path has been changed. So I've used FindFirstChangeNotification and WaitForMultipleObjects (same as a sample in MSDN document).

As I read the document when I use INFINITE for time-out of wait function, it will not be timed out. But in my sample after about one minute, wait function will be timed out.

Do you know what's the problem?

Mehdi

Re: Change Notification

Heath Stewart9-Dec-03 3:02

9-Dec-03 3:02

You should be using the FileSystemWatcher component instead. It already wraps all the native functionality up in an easy-to-use component. You can configure the FileSystemWatcher to watch for new, changed, or deleted files and it will fire events when what you want to watch occurs (like changed files or directories) with information about what was changed (one tip: the Changed event is fired three times for each change regardless of file size - after lots of research into event the native methods that the FileSystemWatcher wraps, I still can't figure out why - just make sure your code accomodates that).

As far as your problem goes, are you actually doing this using C#? INFINITE is actually a pre-proc definition for 0xffffffff (you could declare this as a const in C#) and if you're passing this as a string, the function will most likely use the default timeout.

Folder Permissions

Mauricio Ritter9-Dec-03 2:50

Mauricio Ritter

9-Dec-03 2:50

Hi guys,

I need to give permission to an specific folder to a user using C#. Does anyone ever done that ? Is there any class capable of changing files and folders permissions in .NET ?

thanks in advance

Mauricio Ritter - Brazil
Sonorking now: 100.13560 MRitter

English is not my native language so, if you find any spelling erros in my posts, please let me know.

Re: Folder Permissions

Heath Stewart9-Dec-03 2:56

9-Dec-03 2:56

No, there are no classes in the .NET base class library that can do this, but there are ways you can P/Invoke the necessary functions. Search the comments for this forum, as I know we've talked about it before. I also remember seeing an article or two here on CP about the topic as well.

Design Technique

Ken Galer9-Dec-03 2:36

Ken Galer

9-Dec-03 2:36

When initially laying out the project, or a portion of the project, is it better to start with the interfaces and save the implementation code until later or just write the classes and then write the code that uses them?

Stated another way, Top down or Bottom up?

Thanks,

Ken Galer
Electrical Engineer
Preferred Utilities Corp.
Danbury, CT 06810

Re: Design Technique

Heath Stewart9-Dec-03 2:54

9-Dec-03 2:54

First, create a good design and then go either way. When it comes to UI logic, though (like handling click events and what-not), it's far easier to design the UI first. I personally like creating all my "utility" classes first, though. But jumping into either the front- or back-end without a good design is like diving into a pool without first checking the depth.

Also, when working with data-driven applications, it's better to develop at least the majority of your database elements (tables, views, stored procs, etc.) first. Creating business objects around these is also helpful, but not always necessary.

Re: Design Technique

hazzem elrefai9-Dec-03 22:47

9-Dec-03 22:47

i agree with u Heath Stewart
and i want to say that the analysing phase in so important and evry day in analysing save 5 days in implementaion time, and u can not start the first step in implementaion unless u finished the last step in analysing and design and u r already know what u r going to do till the end

Re: Design Technique

Ken Galer10-Dec-03 2:33

Ken Galer

10-Dec-03 2:33

I understand what both of are saying and agree. I think that I mis-stated the question.

Under the covers of the GUI, when designing whatever custom classes you require and their interfaces, do you normaly design the class:interfaces first and then the classes themselves after you are sure that you can use the classes the why you like?

I'm a C programmer trying to explicitly cast myself as a C# programmer so this is coming from a newbi.

Having just finished the chapter and FINALLY understanding the concept of interfaces ( i hope ) it seems to me that interfaces can act as sort of a prototype for the class.

Do you gyz, as experienced programmers in C#, find this to be useful or does it turn out to be not an issue?

Thanks

Ken Galer
Electrical Engineer
Preferred Utilities Corp.
Danbury, CT 06810

Word object

hazzem elrefai8-Dec-03 23:57

8-Dec-03 23:57

i have got code that use Microsoft spell checker, but when i tryed to compile it i have got erorr in this line:

////////////////
using Word;
//////////////

the erorr is :-

"The type or namespace name 'Word' could not be found (are you missing a using directive or an assembly reference?)"

so i wanna know how to make my application show word class

and thnx in advance

Colin Angus Mackay9-Dec-03 0:19

9-Dec-03 0:19

using Office = Microsoft.Office.Core;
using Word = Microsoft.Office.Interop.Word;

--Colin Mackay--

"In the confrontation between the stream and the rock, the stream always wins - not through strength but perseverance." (H. Jackson Brown)

Enumerators in .NET: See how to customise foreach loops with C#

hazzem elrefai9-Dec-03 0:35

9-Dec-03 0:35

i typed the full path but the code doesn't compile at all
this code is:
private void btn_create_Click(object sender, System.EventArgs e)
{
Microsoft.Office.Interop.Word.Application newApp = new Microsoft.Office.Interop.Word.Application();

l_status.Text+="object instantiated\n";

object Source="c:\\abc\\dat.doc";
object Target="c:\\abc\\Target.rtf";

object Unknown =Type.Missing;

// Source document open here
// Additional Parameters are not known so that are
// set as a missing type
newApp.Documents.Open(ref Source,ref Unknown,
ref Unknown,ref Unknown,ref Unknown,
ref Unknown,ref Unknown,ref Unknown,
ref Unknown,ref Unknown,ref Unknown,
ref Unknown,ref Unknown,ref Unknown,ref Unknown);
l_status.Text+="file opened\n";

// Specifying the format in which you want the output file
object format = Microsoft.Office.Interop.Word.WdSaveFormat.wdFormatRTF;

l_status.Text+="new format created";

//Changing the format of the document
newApp.ActiveDocument.SaveAs(ref Target,ref format,
ref Unknown,ref Unknown,ref Unknown,
ref Unknown,ref Unknown,ref Unknown,
ref Unknown,ref Unknown,ref Unknown,
ref Unknown,ref Unknown,ref Unknown,
ref Unknown,ref Unknown);

l_status.Text+="new file saved \n";

// for closing the application
newApp.Quit(ref Unknown,ref Unknown,ref Unknown);

l_status.Text+="object closed \n";
}

===============================================
the error message is :

An unhandled exception of type 'System.Runtime.InteropServices.COMException' occurred in code_container.exe

Additional information: The server threw an exception.

Colin Angus Mackay9-Dec-03 0:56

9-Dec-03 0:56

hazzem elrefai wrote:
An unhandled exception of type 'System.Runtime.InteropServices.COMException' occurred in code_container.exe

Indicates that the code has compiled. You have a runtime error.

What line did this happen on?

--Colin Mackay--

hazzem elrefai9-Dec-03 1:17

9-Dec-03 1:17

the error in the main finction line :
and i couldn't get any meaningful data from this erorr

static void Main()
{
Application.Run(new MainForm());
}

Colin Angus Mackay9-Dec-03 2:15

9-Dec-03 2:15

I suspect this is where the exception was CAUGHT. Not where it was generated/thrown.

static void Main() 
{
try
{
Application.Run(new MainForm());
}
catch(Exception e)
{
Debug.WriteLine(e.Message);
Debug.WriteLine(e.StackTrace);
}
}

Will write to the output the location that the error was generated. This will help with solving the problem.

--Colin Mackay--

hazzem elrefai9-Dec-03 2:35

9-Dec-03 2:35

i used try catch statements and the erorr is comming from this line:

newApp.Documents.Open(ref Source,ref Unknown,
ref Unknown,ref Unknown,ref Unknown,
ref Unknown,ref Unknown,ref Unknown,
ref Unknown,ref Unknown,ref Unknown,
ref Unknown,ref Unknown,ref Unknown,ref Unknown);

plz keep with me and this will be apreciated
thnx another time

Heath Stewart9-Dec-03 2:51

9-Dec-03 2:51

Colin, note that putting a try-catch around Application.Run only works when an exception causes the application message pump to terminate. This is usually not the case. The try-catch should be as local to the problem as possible (like in the original poster's code to create the Word app and open the document). You can also handle the AppDomain.UnhandledException event.

Colin Angus Mackay9-Dec-03 3:08

9-Dec-03 3:08

Heath Stewart wrote:
Colin, note that putting a try-catch around Application.Run only works when an exception causes the application message pump to terminate

True, like happened here. I realise that the try...catch would be better placed else where but trying to help quickly I figured it was easiest to put round the Application.Run.

--Colin Mackay--

hazzem elrefai9-Dec-03 3:20

9-Dec-03 3:20

iam so confised now,coz i can not run my application yet
and i do not know what is the problem exactly.

Colin Angus Mackay9-Dec-03 3:29

9-Dec-03 3:29

Well, it looks like your code was copied from the documentation. So I don't see much difference between that and MSDN. Are you using a WordProject?

--Colin Mackay--

hazzem elrefai9-Dec-03 3:35

9-Dec-03 3:35

i do not know what is word project exactly
but if it is wizard in vs.net,then i do not use it and it doesn't there
iam using vs.net2003 profissional
thanx

Colin Angus Mackay9-Dec-03 3:45

9-Dec-03 3:45

I'm using VS2003 and Office 2003 (So it might be an office thing) Anyway - I've emailed you the skeleton of the WordProject - it might provide clues to help with your problem. (Its easy for me because it does all the hard work getting everything integrated - You may have to change the project properties because the startup command line may be different in your case)

--Colin Mackay--

hazzem elrefai9-Dec-03 4:29