'Declaration Public ReadOnly Property ValidationRules As ObservableCollection(Of ValidationRule)
public ObservableCollection<ValidationRule> ValidationRules {get;}
ValidationRules property lets you specify one or more ValidationRule objects with which to validate the data value. The value being tested against this ValueConstraint object much match all the validation rules specified via this property for it be considered a valid value.
ValidationRule class lets you provide custom validation logic by deriving a class from it and supplying the custom validation logic in the Validate method, which is an abstract method on the ValidationRule.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2