As the user completes a form, individual properties are validated. To validate an entire form at once, the same approach is used; however, each property is validated, one by one, until all are validated, or until one is deemed invalid.
IsComplete method of the
DataErrorValidator attempts to validate each known property and accepts handlers that are invoked when one of the following three conditions is met:
completeAction—The viewmodel is complete; that is, no properties have associated data-validation errors.
incompleteAction—The viewmodel is incomplete; that is, one or more properties have an associated ...