Today, while I was sitting with Matan, a new programmer at our team, for a code review - I saw one of the worst practices that each new programmer and even experienced programmers are dealing with during their coding/reading in .Net, the Exception rethrow mechanism.
I would like to show here two code examples for best and worst practices:
I wrote this method for further usage:
static void ThrowNotImplementedException ()
{
throw new NotImplementedException("not implemented causes in here");
}
Worst Practice Example:
try
{
ThrowNotImplementedException();
}
catch (NotImplementedException nie)
{
nie.HelpLink = "I am here!!!";
throw nie;
}
Best Practice Example:
try
{
ThrowNotImplementedException();
}
catch (NotImplementedException nie)
{
nie.HelpLink = "I am here!!!";
throw;
}
If you are looking at those code snippets and say to yourself: what? this one is for beginners, so first - I agree with you, secondly stop talking to yourself!
but still there are many programmers that don't remember, or don't even know this case, I want to show you the difference between those two cases:
stack trace results:
Worst Practice:
Best Practice:
Pay attention to the difference between the stack traces which the worst practice do not include the method that caused the Exception! Enjoy debugging.
Last minute editing:
I opened the ILDASM (my favorite tool) and looked at the difference between those two:
throw x; will convert into assembly command named throw.
throw ; will convert into assembly command named rethrow.
I hope this article will help you remember the differences.