Rule #2

I mentioned that Rule #1 was "If you catch an exception, you better record it or re-throw it." Today I will talk about the next rule in the series.

Rule #2: If you throw or catch exceptions, you should use the finally clause to clean up after yourself.

When you throw an exception, or catch an exception, one of the biggest things that happens is that you start to move outside the boundaries of the flow mechanism that you had in place. OK, what this really means is that when you throw or catch you skip a lot of code. If you are using resources that are not simple .NET objects, you need to clean up after yourself. The last part of the Try ... Catch ... Finally block is the Finally clause and this helps you clean up.

The code that you put in the Finally clause is always executed at the end of the Try ... Catch block. So, if you re-throw the exception, throw a new exception or, regretfully, ignore the exception, the code in the Finally clause will be executed. This give you opportunity to clean up after yourself by disposing of those resources and objects that are not simple .NET objects. This includes things like file handles, SQL Server connections, or other resources not necessarily handled by managed .NET code.

This does a lot of things, not the least of which is ensure that your applications does not run out of those resources!!! So, like I always tell my girls when they leave the kitchen table, "clean up after yourself, because no one else is going to do it for you."