Conclusion

Good work! Try the interactive sample to see validation in action.

Note: The only valid credentials are [email protected] and CorrectHorseBatteryStaple.

Summary

• DataAnnotation attributes are the simplest form of validation.
• The Validator control can be used to show validation messages.
• Custom errors can be created in commands using the AddModelError extension method.

Note: There are other validation concepts like IValidatableObject, the ValidationSummary control, and the Validation.Target attached property. These are beyond the scope of this lesson.