validation

After my previous post on Validating Your Configuration, one of my colleagues made an interesting point, paraphrasing: I want to know if the configuration is valid earlier than that. At build time preferably. I don’t want my service to not start if part of it is invalid. There are two points here, namely when to validate, and what to do with the results of validation. Handling Validation Results If your configuration is invalid, you’d think the service should fail to start, as it might be configured in a dangerous manner....

As I have written many times before, your application’s configuration should be strongly typed and validated that it loads correctly at startup. This means not only that the source values (typically all represented as strings) can be converted to the target types (int, Uri, TimeSpan etc) but that the values are semantically valid too. For example, if you have a web.config file with the following AppSetting, and a configuration class to go with it:...