Validation.HasError Attached Property
Gets a value that indicates whether any binding on the target element has a validation error.
Assembly: System.Windows (in System.Windows.dll)
The attached property does not have a conventional XAML usage in the form <object Validation.HasError="true" .../>. In WPF, data validation is sometimes performed with property triggers where Validation.HasError is used as a property condition to check the Property attribute value of a Trigger. Validation.HasError does appear in WPF XAML as an attribute value instead of the attribute. However, Silverlight does not use triggers in this capacity.
In Silverlight, handlers for events, such as SizeChanged, can check any pending error state. Such event handlers might check for the Validation.HasError attached property on objects in code, but would either call the GetHasError method or call the GetValue method with the HasErrorProperty identifier.
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.