What are the best practices for custom validation in ASP.NET?

What are the best practices for custom validation in ASP.NET?

When implementing custom validation in ASP.NET, consider the following best practices: 1. Use Data Annotations for simple validations. 2. Create custom validation attributes for complex rules. 3. Ensure your validation logic is reusable and maintainable. 4. Provide clear error messages to users. 5. Test your validation thoroughly.

Can you explain how to create a custom validation attribute?

Sure! To create a custom validation attribute, inherit from the ValidationAttribute class and override the IsValid method. In this method, implement your validation logic and return ValidationResult.Success if valid, or a new ValidationResult with an error message if not.

What are some common mistakes to avoid?

Common mistakes include: 1. Not reusing validation logic, leading to code duplication. 2. Failing to provide user-friendly error messages. 3. Ignoring performance implications of complex validation logic. 4. Not testing validation thoroughly across different scenarios.

How can I test my custom validation?

You can test your custom validation by writing unit tests that cover various input scenarios. Use a testing framework like NUnit or xUnit to create tests that check both valid and invalid inputs, ensuring your validation logic behaves as expected.