uncaught exception handlers
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No you're not wrong, you should catch what the error is, but if you don't KNOW what is is (thus you got the unhanded exception) you can add a general
catch (Exception err)
{
}which can allow you diagnose it/ silently write a log entry for the problem to be corrected. If you are doing: int i = 3 + 4; there isn't a need for a try-catch but normally with FileIO and other process (that are slower than the try catch block itself) they are fine.... It's hard to judge when/where you need them as you are starting off.
-Spacix All your skynet questions[^] belong to solved
Thanks Spacix, I think when you get exception, and uncaught it, your program will terminate and you will get information from console, for example. In this way, you can know what exception happens. So, no need to catch all exceptions, right? regards, George
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Actually, he is right. You should only do a catch all when performing an operation that you're willing to let fail, or at the top level, to report errors to an end user and write them to a log. The only reason to catch all, is because you're looking to work out why your code is failing, and to log an error.
Christian Graus Please read this if you don't understand the answer I've given you "also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )
Thanks Christian, I agree with your points. Any ideas to my original question? About using using Application.ThreadException or AppDomain.CurrentDomain.UnhandledException in console/Windows service application? regards, George
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Spacix One wrote:
which can allow you diagnose it
And if nothing else, I guess that's the answer to the orriginal question; set a break point in the catch block and Visual Studio will tell you the type of the exception (and hence you can modify the code to catch exactly that). Does anyone know if a try...catch block affects the performance of the try block code? I know it has a performance hit on hitting the block, but I wonder if it has a continuing effect beyond that.
Thanks Derek, I agree with your points. Any ideas to my original question? About using using Application.ThreadException or AppDomain.CurrentDomain.UnhandledException in console/Windows service application? regards, George
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Thanks Derek, 1.
Derek Bartram wrote:
to avoid using try...catch as much as possible due to the massive performance hit it
Do you mean catching all exception will degrade performance or you mean generally exception handling approach will degrade performance? 2. Do you have any documents to support your points? :-) regards, George
I've just done some googling on the subject (and confirmed via a lecturer from Uni).... 1) There is a performance hit running code inside a try...catch block but it's negligable 2) There is a BIG performance hit when an exception occurs So, 3) Use try...catch for only catching untestable errors and not controlling programming flow. http://www.javaworld.com/javaworld/javaqa/2001-07/04-qa-0727-try.html[^] http://aspadvice.com/blogs/name/archive/2008/01/18/Try-Catch-Performance-in-CSharp_3A00_-A-Simple-Test-Response.aspx[^]
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Thanks Derek, I agree with your points. Any ideas to my original question? About using using Application.ThreadException or AppDomain.CurrentDomain.UnhandledException in console/Windows service application? regards, George
Yes.... run the code with catch (Exception err) and output err.GetType() somehow (Console.WriteLine will do). You'll then know the type of the exception raised so you can go back and modify catch (Exception err) to the specific type.
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I've just done some googling on the subject (and confirmed via a lecturer from Uni).... 1) There is a performance hit running code inside a try...catch block but it's negligable 2) There is a BIG performance hit when an exception occurs So, 3) Use try...catch for only catching untestable errors and not controlling programming flow. http://www.javaworld.com/javaworld/javaqa/2001-07/04-qa-0727-try.html[^] http://aspadvice.com/blogs/name/archive/2008/01/18/Try-Catch-Performance-in-CSharp_3A00_-A-Simple-Test-Response.aspx[^]
Thanks Derek, Cool!! Your 1st link is Java... :-) I am interested in your 2nd link. But confused what means "catching untestable errors" and "not controlling programming flow"? Could you show some samples please? regards, George
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Yes.... run the code with catch (Exception err) and output err.GetType() somehow (Console.WriteLine will do). You'll then know the type of the exception raised so you can go back and modify catch (Exception err) to the specific type.
Thanks Derek, I agree with your exception handling approach. Any answers or comments to my original question? :-) regards, George
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Hello everyone, I am new to how to catch uncaught exception. From some self-learning, I think we should use, event handler for AppDomain.CurrentDomain.UnhandledException other than Application.ThreadException if we are writing console or Windows service, right? Application.ThreadException is for Windows Form application, not console and Windows Service application? thanks in advance, George
For a console app, you could put try/catch around the guts of your main() function.
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
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"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001 -
For a console app, you could put try/catch around the guts of your main() function.
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
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"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001Hi John, I think in this approach, we can only catch exception from main thread, right? (Suppose we create new threads from main methods, then we can not catch exception from other threads in main method?) regards, George
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Correct me if i'm wrong, but generally catching things using catch (Exception err) is bad practice? You should try any catch specific exceptions otherwise you get a much greater performance hit I believe. *A point always worth mentioning (particularily to people new to the language); try to avoid using try...catch as much as possible due to the massive performance hit it (hundreds of times slower to process try...catch than simple math functions).
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For a console app, you could put try/catch around the guts of your main() function.
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
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"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001Indeed, I always put a try/catch in the Main.
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Thanks for the link, an interesting article. I probably didn't specify 'massive' which didn't help; I meant relative to performing an if test to prevent the exception.
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Thanks N a v a n e e t h, What do you mean "windows applications"? I have checked again in VS 2008, there is not a project type names "windows applications". Do you mean Windows Forms application? regards, George
George_George wrote:
Windows Forms application?
Yes. Also you can wrap the
main()method intry catchblocks. So it can handle all exceptions.All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
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George_George wrote:
Windows Forms application?
Yes. Also you can wrap the
main()method intry catchblocks. So it can handle all exceptions.All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
No, N a v a n e e t h. Not catch all exceptions, you can not catch exception from other threads? Right? regards, George
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Thanks PIEBALDconsult, Good reference. :-) regards, George
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Thanks for the link, an interesting article. I probably didn't specify 'massive' which didn't help; I meant relative to performing an if test to prevent the exception.
Thanks Derek, What do you mean "didn't specify 'massive' which didn't help" and "relative to performing an if test to prevent the exception"? Could you show more description or some pseudo code about your approach please? regards, George
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No, N a v a n e e t h. Not catch all exceptions, you can not catch exception from other threads? Right? regards, George
George_George wrote:
you can not catch exception from other threads? Right?
Yes. You are right. I missed that. Hook
AppDomain.UnhandledExceptionwhich handles all exception other than the ones I specified in my first message.All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
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George_George wrote:
you can not catch exception from other threads? Right?
Yes. You are right. I missed that. Hook
AppDomain.UnhandledExceptionwhich handles all exception other than the ones I specified in my first message.All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia How to use google | Ask smart questions
You mean "Also exceptions occurring in unmanaged resources won't be handled too" will not be handled? regards, George
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Spacix One wrote:
which can allow you diagnose it
And if nothing else, I guess that's the answer to the orriginal question; set a break point in the catch block and Visual Studio will tell you the type of the exception (and hence you can modify the code to catch exactly that). Does anyone know if a try...catch block affects the performance of the try block code? I know it has a performance hit on hitting the block, but I wonder if it has a continuing effect beyond that.
Derek Bartram wrote:
Does anyone know if a try...catch block affects the performance of the try block code? I know it has a performance hit on hitting the block, but I wonder if it has a continuing effect beyond that.
I once worked on a project where the Project Lead insisted on try catch blocks in every bloody method. I did some performance testing and could determine definitive costs with the setup and teardown of the block, but was unable to measure any discernable difference to the code internally. However the code was entirely managed, perhaps wrapping unmanaged code has other implications.
I'm largely language agnostic
After a while they all bug me :doh:
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Hi John, I think in this approach, we can only catch exception from main thread, right? (Suppose we create new threads from main methods, then we can not catch exception from other threads in main method?) regards, George
If you wanted to go that far you can catch errors in your thread method also... Are you looking for on error resume next type functionally? If so might be better to use VB.NET as C# doesn't allow for that coding horror :) You need to remember the following: Using exceptions to control programming logic is is the same as having car insurance to repair the damange after rolling off a cliff instead of setting the parking break to prevent it from rolling away.
-Spacix All your skynet questions[^] belong to solved
