DataErrorNotifier class in the downloadable sample code is a reusable implementation of the
DataErrorNotifier makes implementing asynchronous validation easy. With the addition of a single validation method to your viewmodel,
DataErrorNotifier manages the list of errors and takes care of raising data error events. Furthermore, validation can be restricted by registering only those properties that you want to be validated.
DataErrorNotifier is designed to validate classes that implement a custom
IValidateData interface, such as the
ViewModelBase class. The validation logic has been decoupled from the
ViewModelBase class to be reusable for other types ...