It's been quiet around here the last month, as I've been "busy" finishing the March sprint of our current project - after skiing in Avoriaz, France for one week first. Today I'm back after a one week Easter vacation, skiing in Trysil, Norway.
The production version of EntLib 3 was released last week, and I have downloaded it and tested the validation application block with our WCF services. The first thing I noticed when recompiling was that a breaking change has been introduced in EntLib3 April 2007: the attribute parameters for specifying a custom validation message are gone from the attribute constructors. You now need to use named parameters to specify your message in a VAB attribute, e.g. MessageTemplate = "message" as shown here:
[RegexValidator(@"^.*$", RegexOptions.IgnoreCase, MessageTemplate = "Invalid ticket")]
When my code again compiled, I checked if some of the issues I've reported in the February CTP had been fixed. The most serious issue for my current project is validating recursive object collections, e.g. a structure of folders that can contain files and sub-folders.
The [ObjectCollectionValidator] issue has not been fixed, the NUnit tests still silently fails - caused by a stack overflow due to an infinite loop when building the validator tree for the recursive object structure.
The second issue is that the [IgnoreNulls] attribute should get a sibling [IgnoreNullOrEmpty] attribute for strings. This is especially important for validating WCF messages and data contracts; if an optional string element is not specified (null) in the message on-the-wire, the DataContractSerializer will deserialize the missing string element by applying the default value for strings: String.Empty. So, now the null value sent by the client is actually String.Empty when applying the validation rules on the server, and thus the [IgnoreNulls] rule is not sufficient for easily validating WCF messages.
Specifying a set of validation attributes to build a ruleset for covering "ignore if null or empty, otherwise string must be 5-10 chars long" using the [ValidatorComposition] attribute is not simple, thus I have logged the need for [IgnoreNullOrEmpty] as an issue.