1) To my understanding, in a three-tier Asp.Net application we should implement exception handling in the following way:
a – we should put try-catch block around block of code ( located in any of the three layers ) from which we expect the page to gracefully recover from ( when this code generates an exception )?
b – we shouldn’t put try-catch blocks around code ( located in either of the three layers ) from which we don’t expect the page to gracefully recover from. Instead, Asp.Net application should always manage these unhandled exceptions through global exception handler ( Application_Error/Page_Error )?
2) Is the main benefit of managing unhandled exceptions through Application_Error/Page_Error the fact that this way we centralize error handling in one location?
After all, we could achieve the same results even if these unhandled exceptions (thrown in any of the three layers ) were instead handled ( logged, user redirected to custom error page … ) at the spot where they were thrown?!
thank you
1a) is correct.
1b) is sort of correct; you may let the exception go up the stack from your model/business layers to the presentation, and display an error message. It doesn’t have to go all the way to the Application_Error; Page_Error may be good, but some exceptions might be (relatively) common enough that, while you can not gracefully recover, you should have specific error messages related to them in some contexts.
2) basically; and also as a ‘catch all’ for exceptions you have not been able to predict and catch in more specific places.