Best Practice for Exception Handling in a Windows Forms Application?

Question

I\'m currently in the process of writing my first Windows Forms application. I\'ve read a few C# books now so I\'ve got a relatively good understanding of what language feat

Answer 1

Here are a few guidelines that I follow

1. Fail-Fast: This is more of a exception generating guideline, For every assumption that you make and every parameter that you are getting into a function do a check to make sure that you're starting off with the right data and that the assumptions you're making are correct. Typical checks include, argument not null, argument in expected range etc.

2. When rethrowing preserve stack trace - This simply translates to using throw when rethrowing instead of throw new Exception(). Alternatively if you feel that you can add more information then wrap the original exception as an inner exception. But if you're catching an exception only to log it then definitely use throw;

3. Do not catch exceptions that you cannot handle, so don't worry about things like OutOfMemoryException because if they occur you won't be able to do much anyways.

4. Do hook global exception handlers and make sure to log as much information as possible. For winforms hook both the appdomain and thread unhandled exception events.

5. Performance should only be taken into consideration when you've analyzed the code and seen that it's causing a performance bottleneck, by default optimize for readability and design. So about your original question on the file existence check, I would say it depends, If you can do something about the file not being there, then yes do that check otherwise if all you're going to do is throw an exception if the file's not there then I don't see the point.

6. There are definitely times when empty catch blocks are required, I think people who say otherwise have not worked on codebases that have evolved over several releases. But they should be commented and reviewed to make sure that they're really needed. The most typical example is developers using try/catch to convert string to integer instead of using ParseInt().

7. If you expect the caller of your code to be able to handle error conditions then create custom exceptions that detail what the un excepected situation is and provide relevant information. Otherwise just stick to built-in exception types as much as possible.