Globally catch exceptions in a WPF application

Question

We are having a WPF application where parts of it may throw exceptions at runtime  I d like to globally catch any unhandled exception and log them  but otherwise continue program execution as if nothing happened  kinda like VB s On Error Resume Next    Is this possible in C   And if so  where exactly would I need to put the exception handling code   Currently I can t see any single point where I could wrap a try catch around and which would catch all exceptions that could occur  And even then I would have left whatever has been executed because of the catch  Or am I thinking in horribly wrong directions here   ETA  Because many people below pointed it out  The application is not for controlling nuclear power plants  If it crashes it s not that much a big deal but random exceptions that are mostly UI-related are a nuisance in the context where it would be used  There were  and probably still are  a few of those and since it uses a plugin architecture and may be extended by others  also students in that case  so no experienced developers that are able to write completely error-free code    As for the exceptions that get caught  I do log them to a log file  including the complete stack trace  That was the whole point of that exercise  Just to counter those people  that were taking my analogy to VB s OERN too literally   I know that blindly ignoring certain classes of errors is dangerous and might corrupt my application instance  As said before  this program isn t mission-critical for anyone  No-one in their right mind would bet the survival of the human civilization on it  It s simply a little tool for testing certain design approaches wrt  software engineering   For the immediate use of the application there are not many things that can happen on an exception    No exception handling     error dialog and application exit  Experiment has to be repeated  though likely with another subject  No errors have been logged  which is unfortunate  Generic exception handling     benign error trapped  no harm done  This should be the common case judged from all errors we were seeing during development  Ignoring this kind of errors should have no immediate consequences  the core data structures are tested well enough that they will easily survive this  Generic exception handling     serious error trapped  possibly crash at a later point  This may happen rarely  We ve never seen it so far  The error is logged anyway and a crash might be inevitable  So this is conceptually similar to the very first case  Except that we have a stack trace  And in the majority of cases the user won t even notice    As for the experiment data generated by the program  A serious error would at worst just cause no data to be recorded  Subtle changes that change the result of the experiment ever so slightly are pretty unlikely  And even in that case  if the results seem dubious the error was logged  one can still throw away that data point if it s a total outlier   To summarize  Yes  I consider myself still at least partially sane and I don t consider a global exception handling routine which leaves the program running to be necessarily totally evil  As said twice before  such a decision might be valid  depending on the application  In this case it was judged a valid decision and not total and utter bullshit  For any other application that decision might look different  But please don t accuse me or the other people who worked on that project to potentially blow up the world just because we re ignoring errors   Side note  There is exactly one user for that application  It s not something like Windows or Office that gets used by millions where the cost of having exceptions bubble to the user at all would be very different in the first place already

User · Answer

In addition what others mentioned here  note that combining the  Application DispatcherUnhandledException  and its similars  with    lt configuration gt     lt runtime gt         lt legacyUnhandledExceptionPolicy enabled  1    gt     lt  runtime gt   lt  configuration gt    in the app config will prevent your secondary threads exception from shutting down the application

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Example code using NLog that will catch exceptions thrown from all threads in the AppDomain  from the UI dispatcher thread and from the async functions   App xaml cs    public partial class App   Application       private static Logger  logger   LogManager GetCurrentClassLogger         protected override void OnStartup StartupEventArgs e                base OnStartup e            SetupExceptionHandling               private void SetupExceptionHandling                 AppDomain CurrentDomain UnhandledException     s  e    gt              LogUnhandledException  Exception e ExceptionObject   AppDomain CurrentDomain UnhandledException             DispatcherUnhandledException     s  e    gt                        LogUnhandledException e Exception   Application Current DispatcherUnhandledException                e Handled   true                      TaskScheduler UnobservedTaskException     s  e    gt                        LogUnhandledException e Exception   TaskScheduler UnobservedTaskException                e SetObserved                          private void LogUnhandledException Exception exception  string source                string message     Unhandled exception   source             try                       System Reflection AssemblyName assemblyName   System Reflection Assembly GetExecutingAssembly   GetName                message   string Format  Unhandled exception in  0  v 1    assemblyName Name  assemblyName Version                     catch  Exception ex                         logger Error ex   Exception in LogUnhandledException                      finally                        logger Error exception  message

User · Answer

Use the Application DispatcherUnhandledException Event  See this question for  a summary  see Drew Noakes  answer    Be aware that there ll be still exceptions which preclude a successful resuming of your application  like after a stack overflow  exhausted memory  or lost network connectivity while you re trying to save to the database

User · Answer

AppDomain UnhandledException Event     This event provides notification of uncaught exceptions  It allows the   application to log information about the exception before the system   default handler reports the exception to the user and terminates the   application       public App              AppDomain currentDomain   AppDomain CurrentDomain        currentDomain UnhandledException    new UnhandledExceptionEventHandler MyHandler                static void MyHandler object sender  UnhandledExceptionEventArgs args              Exception e    Exception  args ExceptionObject        Console WriteLine  MyHandler caught       e Message         Console WriteLine  Runtime terminating   0    args IsTerminating             If the UnhandledException event is handled in the default application   domain  it is raised there for any unhandled exception in any thread    no matter what application domain the thread started in  If the thread   started in an application domain that has an event handler for   UnhandledException  the event is raised in that application domain  If   that application domain is not the default application domain  and   there is also an event handler in the default application domain  the   event is raised in both application domains       For example  suppose a thread starts in application domain  AD1     calls a method in application domain  AD2   and from there calls a   method in application domain  AD3   where it throws an exception  The   first application domain in which the UnhandledException event can be   raised is  AD1   If that application domain is not the default   application domain  the event can also be raised in the default   application domain

User · Answer

Like  VB s On Error Resume Next   That sounds kind of scary  First recommendation is don t do it  Second recommendation is don t do it and don t think about it  You need to isolate your faults better  As to how to approach this problem  it depends on how you re code is structured  If you are using a pattern like MVC or the like then this shouldn t be too difficult and would definitely not require a global exception swallower  Secondly  look for a good logging library like log4net or use tracing  We d need to know more details like what kinds of exceptions you re talking about and what parts of your application may result in exceptions being thrown

User · Answer

Here is complete example using NLog  using NLog  using System  using System Windows   namespace MyApp            lt summary gt          Interaction logic for App xaml          lt  summary gt      public partial class App   Application               private static Logger logger   LogManager GetCurrentClassLogger             public App                         var currentDomain   AppDomain CurrentDomain              currentDomain UnhandledException    CurrentDomain UnhandledException                     private void CurrentDomain UnhandledException object sender  UnhandledExceptionEventArgs e                        var ex    Exception e ExceptionObject              logger Error  UnhandledException caught       ex Message               logger Error  UnhandledException StackTrace       ex StackTrace               logger Fatal  Runtime terminating   0    e IsTerminating

[c#] Globally catch exceptions in a WPF application?

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