Try..Catch blocks always expensive? [duplicate]

Answer 1

In general, modern compilers impose only a minimal cost on try blocks unless an exception is thrown. They still shouldn't be used for program flow control, as they aren't as obvious as standard flow constructs. An exception is essentially equivalent to a COME FROM statement.

Answer 2

Exceptions are only expensive if an exception is thrown. I'm sure there is some very minimal cost to setting up up a Try..Catch block but it is by far outweighed by the cost of not catching the exception at all and having your program crash. As others have pointed out, Try..Catch blocks should only be used for exceptional circumstances.

Answer 3

try..catch blocks should never be used as a tool for program flow control.

Read this thread if you're unconvinced.

Answer 4

It's only expensive if the exception is thrown, but that's not an excuse to use exceptions as normal flow control.

If you can pre-validate something to avoid an exception occurring in the first place, then do so. E.g. instead of what you posted, something like this would be preferable:

string invalidAddress = "notvalid@@@@@@lolzors.bomb";
return MailAddressValidator.IsValid(invalidAddress ); // doesn't cause exception

The exception to the rule is when you'd have to roll your own version of a complicated method (e.g. something found in the base class library that doesn't have a TryParse method) just to avoid an exception that, in the grand scheme of things, just doesn't matter.

If you are unsure, profile using representative data. If it's a user entering data in a client app form every other second, it won't matter. However, if it's a service for processing batches of thousands of email addresses that could come from anywhere, you ought to be sure of your assumptions.