What is the preferred method (one that has minimal custom code and ideally is portable to planned future versions of MVC without extra widgets) to validate common datatypes (e.g. e-mail addresses, dates, phone numbers) at both the client and server?
MY RESEARCH
I'm going to list a few methods I've seen, approximately from worst to best (IMHO). I'm currently using the last method listed. I'll focus on e-mail validation in this post, to keep things clear.
REGEX AND/OR CUSTOM VALIDATION ATTRIBUTE
I know jQuery validate includes some common datatypes including e-mail, and additional plugins exist for download (e.g. integer, max words). So custom regex's here are not the right answer.
I know how to write a custom validator from scratch at server and client, and even to 'adapt' an existing client-side rule to a custom attribute when using the unobtrusive connector. http://bradwilson.typepad.com/blog/2010/10/mvc3-unobtrusive-validation.html but it probably doesn't make sense for such a common type as e-mail address.
Nor, probably, to extend a regex rule, as per: http://www.pagedesigners.co.nz/2011/02/asp-net-mvc-3-email-validation-with-unobtrusive-jquery-validation/
OVERRIDING STOCK DataType ATTRIBUTE VALIDATORS
.NET includes [System.ComponentModel.DataAnnotations.DataType(DataType.EmailAddress)] This causes always-succeed validation at client or server, and is really only useful out-of-the-box for a tangential purpose of formatting display strings. Overriding the always-succeed validation is possible, as per: http://weblogs.asp.net/srkirkland/archive/2011/02/15/adding-client-validation-to-dataannotations-datatype-attribute.aspx
MVC DATA VALIDATION EXTENSION (VIA NUGET)
A NuGet-downloadable validation extension was released several months ago, and I'm currently using it, but I was surprised to see that it did not leverage the existing DataAnnotations.DataType enum. It makes me wonder if there is some development divergence that I should be avoiding here. http://weblogs.asp.net/srkirkland/archive/2011/02/23/introducing-data-annotations-extensions.aspx Also, it doesn't include phone numbers or US phone numbers.
Any better method?
