C# Discussion Boards - CodeProject

prevent re-opening of application

30-Jan-04 4:03

There's always the topics in the .NET Framework SDK, which is always a good place to start: http://msdn.microsoft.com/library/en-us/cpguide/html/cpconCOMRegularExpressions.asp[^].

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azusakt29-Jan-04 19:46

azusakt

29-Jan-04 19:46

Dear friends,

I've tried to make a simple application, and built it as an exe. But I got a problem , how can I prevent the application not to be re-opened if it has already been opened?

Could anyone point me the way??, need programming or just simple setting?

Thanks a lot

Kentamanos29-Jan-04 20:03

29-Jan-04 20:03

The best method is probably creating a "named" Mutex (in the System.Threading namespace). When your application first comes up, you try to claim the named Mutex, which is system-wide. If you can't claim it, another instance of the application is already running. The only thing you really have to do is make the name of the Mutex very unique. A good way to create something with a very unique name is to use a GUID.

So you do something like set a string up to be the Mutex name you want, like:

string mutexName = "...";

where you use a GUID in place of the ...

Then do something like:

bool weGotIt = false;
Mutex mutex = new Mutex(true, mutexName, out weGotIt);

if (weGotIt)
{
// Run like normal...
}
else
{
// Exit...another instance of the application already has it...
}

Let me know if I didn't explain this well or if you need more help.

Mazdak30-Jan-04 1:57

Mazdak

30-Jan-04 1:57

Another way is to P/Invoke the FindWindow API in your Load event and if there is one instant of your application exist, exit the program.

Mazy

No sig. available now.

Heath Stewart30-Jan-04 4:00

30-Jan-04 4:00

Using a Mutex is by far the best way, because they are atomic (an ATOM registered in the system). Using FindWindow relies on a window class name and / or a caption, which could already exist whether it's the correct application or not, or the caption for your application might be dynamic so a running instance won't be found by FindWindow. It works for many cases, but not all.

azusakt30-Jan-04 14:18

azusakt

30-Jan-04 14:18

Thank you for all of your replies.

But could you give me a full example simply show me that how to use "Mutex". Is it the traditional way to do?

Thank you

Heath Stewart30-Jan-04 14:39

30-Jan-04 14:39

Kentamanos already did above. You acquire a Mutex with the first instance and the second instance (or more) can't acquire it so you exit the application:

string mutexName = "some unique string";
bool acquired;
new Mutex(true, mutexName, out acquired);
if (acquired)
{
  // Run your main form as the application window.
  Application.Run(new MainForm());
}
else
{
  Application.Exit();
}

Optionally, if you don't acquire the Mutex, you can grab the command line parameters (like a filename) and force the existing process to open a new document (or set focus to the existing document). There are plenty of examples of this here on CodeProject and on the 'net.

Microsoft MVP, Visual C#
My Articles

Bo Hunter30-Jan-04 14:43

Bo Hunter

30-Jan-04 14:43

What do you mean?
Kentamanos has posted it.

Thank You
Bo Hunter

BP12829-Jan-04 18:17

BP128

29-Jan-04 18:17

i am a beginner really and i thaught i had the right program and i want to know if the c# builder tool was free and if it it is free if some1 could email it to me
Big Grin | :-D

Re: C#

Kentamanos29-Jan-04 19:00

29-Jan-04 19:00

Go here. This is the free .NET Framework SDK, which includes a command line C# compiler. Take a look at the C# samples.

A good place to start with C# is the Quick Start Tutorials.

If you want a free C# IDE (Integrated Development Environment), I've heard good things about Sharp Develop.

You should definitely read a lot of stuff on MSDN.

You should probably pick up a book on C#. If you're new to programming, learn to walk before you run. I'd start with "console applications", and not worry about form based applications or Web applications yet. Don't expect to write a "killer app" from the starting blocks. Smile | :)

Start simple...

DirectX Tutorial

Shree29-Jan-04 17:35

Shree

29-Jan-04 17:35

A lucid tutorial on starting with DirectX

http://www.kuhnstall.de/tutorials.html

Re: DirectX Tutorial

Mazdak29-Jan-04 19:07

Mazdak

29-Jan-04 19:07

Thanks.

Mazy

No sig. available now.

Missing file

BP12829-Jan-04 16:43

BP128

29-Jan-04 16:43

i cannot get OpenPGP can because it is a missing file some1 email it 2 me

Re: Missing file

Kentamanos29-Jan-04 16:51

29-Jan-04 16:51

...and this has to do with C# because?

Re: Missing file

BP12829-Jan-04 16:53

BP128

29-Jan-04 16:53

it is a c# Program!

Re: Missing file

Heath Stewart30-Jan-04 3:37

Automatic WSDL generation

30-Jan-04 3:37

OpenPGP is NOT a C# program! It's a C/C++ program. Understand the difference. If you're having problems with OpenPGP, then see http://www.openpgp.org[^]! This is NOT a C# question and does not belong here. Try the C/C++ forum but search the product web site first that I gave you - finding answers to product-specific questions should obviously lead you to the product's web site.

Kentamanos29-Jan-04 15:48

29-Jan-04 15:48

I'm trying to develop an XML Webservice for work that uses SOAP. It's very easy to get something going quickly, but It's a bit tougher to get it exactly like you want Wink | ;)

.

My current concern is the WSDL that's automatically generated with the "?WSDL" query string is very unstrict (can't blame it, it's not psychic). For instance, every parameter to a method that can be null ends up having its "minOccurs" set to 0. I'd also really like to be able to use some regular expression restrictions for certain types. I'm a big believer in schema validation (which I realize I have to do by hand regardless of what the WSDL says), and I'd like the WSDL to be more strict.

I've searched for quite a while, and I'm not having much luck finding anything. There seems to be a lot of attributes I can use to control the XML serialization of classes, but I haven't seen anything yet that lets me do something like "represent this class with this XmlSchema instance", which might be how I would get my service to create a "good" schema (guessing here).

Should I just give up on making the automatically generated WSDL look good and just write my own WSDL file by hand (and point clients there). It seems like that route would be more of a pain in the butt to maintain, but if that's the only way to make me happy I might go that route. Is there any way I can turn off the automatic WSDL generation (?WSDL querystring on the .asmx) if I go that route?

Kentamanos29-Jan-04 16:09

29-Jan-04 16:09

Hmmm...looks like I might be able to implement IXmlSerializable and have it return the exact schema. I'm going to check that out...

Kentamanos29-Jan-04 16:32

29-Jan-04 16:32

Well just in case someone's following my rambling...

I hate when I figure something out minutes after I posted Smile | :)

.

I spent the most of the day going down the wrong path with all the attributes available for classes that control how XML serialization works. It would appear that at the end of the day, you're better off just going ahead and implementing IXmlSerializable yourself and saving yourself a lot of headaches.

I now need to make sure the proxy generators handle this type of WSDL properly (I doubt classes will enforce restrictions, but at least I'm putting it out there as a "contract" for clients). If the proxy generators (one in IDE and WSDL.exe if nothing else) handle this properly, then I should be set.

Heath Stewart30-Jan-04 3:54

30-Jan-04 3:54

There's a ton of attributes you can use to control a lot of this, although I'm not sure about the regex, and don't remember ever seeing anything like this - but you shouldn't rely stricly on WSDL schema validation since some clients may not do that. Always check params going into your code, so you ultimately control what goes in and out of your methods!

First, there's the attributes in the System.Xml.Serialization namespace, like the XmlRootAttribute and XmlElementAttribute that have an IsNullable property you can set to false. There's also many advanced usage attributes in System.Web.Services.Protocols that let you control the input and output of SOAP and help in the documentation generation for the WSDL, such as using different readers and writers for the generation using the HttpMethodAttribute.

You should use these when you can because it ultimately gives you more control over SOAP and WSDL, and IXmlSerialization is not supposed to be used from your code which means it could change at any time without notice (but I must confess I've used it a few times here and there! Smile | :)

Kentamanos30-Jan-04 6:27

Re: COM+ Catalog Infomation

30-Jan-04 6:27

I know that the web services don't do any sort of validation, and that I'll have to create a handler to do the validation in any event. I just want WSDL that makes sense and is tight as possible, but I'm starting to think that getting it as tight as I would like will be impossible (I'm a big fan of very explicit "contracts").

Implementing IXmlSerializable made the proxy generator (IDE and WSDL.exe) fail to generate anything for data types I tried to define myself. That means we'd have to give them assemblies for those classes or they'd have to write their own class. So I think going the attributes route is definitely the way to go again, and I'll just have to not expect too much from the WSDL Smile | :)

. I actually didn't even notice the IXmlSerializable interface was not supposed to be used. I saw the suggestion in a post (and if I remember correctly it was from a MS VIP or a MS employee). You're right though, it shouldn't really be used.

I missed that IsNullable property. A co-worker claims to have used that and still gets a "minOccurs=0", but I'll check that out in any case.

Thanks for the help!

COM+ Catalog Infomation

kimsangwoo29-Jan-04 14:39

kimsangwoo

29-Jan-04 14:39

I've spent a week on making COM+ ManagementTool displaying COM+ Catalog Infomation using COMAdminCatalogCollection. Most of infomation I'd like to
find was in COMAdminCatalogCollection.
But I couldn't find a way of retrieving imfomation of state of Object activated. I'd like to know how many Object is Activated as if I see the COM+ Management Tool provided in Windows 2003.
Please,Help me.
Any idea will be helpful.

kim

Heath Stewart30-Jan-04 3:45