I have a view model that implements IValidatableObject and also has several validation attributes. When I attempt to call an action on my ApiController, only the attribute validation is performed. Does ASP.NET Web API not support IValidatableObject? What's the alternative for complex validation that cannot be represented by a single attribute?
Edit: Somewhere along the line, I must have fudged something up. The validation mysteriously started working as expected. Looks like IValidatableObject is definitely supported by default.
Not yet tried IValidatableObject on webapi, but it should be supported according to the documentation the Validation provider for DataAnnotations (DataAnnotationsModelValidatorProvider) provide also IValidatableObject validation. See here: http://msdn.microsoft.com/en-us/library/system.web.http.validation.providers(v=vs.108)
Anyway, you can use also Object level ValidationAttribute that you can use to decorated a class...It is not so easy as IValidatableObject, but should work.