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How using try catch for exception handling is best practice

Asked 2013-02-20T06:32:37.503
215

while maintaining my colleague's code from even someone who claims to be a senior developer, I often see the following code:

try
{
  //do something
}
catch
{
  //Do nothing
}

or sometimes they write logging information to log files like following try catch block

try
{
  //do some work
}
catch(Exception exception)
{
   WriteException2LogFile(exception);
}

I am just wondering if what they have done is the best practice? It makes me confused because in my thinking users should know what happens with the system.

c# .net exception try-catch
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1 Answer

330

My exception-handling strategy is:

  • To catch all unhandled exceptions by hooking to the Application.ThreadException event, then decide:

    • For a UI application: to pop it to the user with an apology message (WinForms)
    • For a Service or a Console application: log it to a file (service or console)

Then I always enclose every piece of code that is run externally in try/catch :

  • All events fired by the WinForms infrastructure (Load, Click, SelectedChanged...)
  • All events fired by third party components

Then I enclose in 'try/catch'

  • All the operations that I know might not work all the time (IO operations, calculations with a potential zero division...). In such a case, I throw a new ApplicationException("custom message", innerException) to keep track of what really happened

Additionally, I try my best to sort exceptions correctly. There are exceptions which:

  • need to be shown to the user immediately

  • require some extra processing to put things together when they happen to avoid cascading problems (ie: put .EndUpdate in the finally section during a TreeView fill)

  • the user does not care, but it is important to know what happened. So I always log them:

  • In the event log

  • or in a .log file on the disk

It is a good practice to design some static methods to handle exceptions in the application top level error handlers.

I also force myself to try to:

  • Remember ALL exceptions are bubbled up to the top level. It is not necessary to put exception handlers everywhere.
  • Reusable or deep called functions does not need to display or log exceptions : they ar
answered 2013-02-20T07:07:30.293

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