Read original post at Jerry Nixon's Blog
Many Windows Store apps are content presenters; they require very little data entry and, consequently, very little data validation. But data validation is a core component to a business apps. Is there validation built into the platform? No.
In several XAML frameworks data validation was baked-in. DataAnnotation and ExceptionValidationRule for bindings in WPF. IDataErrorInfo, INotifyDataErrorInfo, and BindingValidationError for setter exceptions in Windows Phone, Silverlight, et al. But these are not an option for a Windows Runtime developer, especially the Universal App developer. And, as we will see in this article, they were never really enough anyway. But, we have options.