How can I create custom validation rules in Fluent Validation?

How can I create custom validation rules in Fluent Validation?

You can create custom validation rules in Fluent Validation by implementing the IPropertyValidator interface or using the RuleFor method with a custom function.

Can you give me an example of a custom rule?

Sure! For instance, you can create a rule that checks if a string is a valid email format like this: RuleFor(x => x.Email).Must(BeAValidEmail).WithMessage("Invalid email format.");.

What if I want to validate a complex object?

You can validate complex objects by chaining rules. For example, RuleFor(x => x.Address).SetValidator(new AddressValidator()); allows you to use a separate validator for the Address property.

Is it possible to reuse custom rules across different models?

Yes, you can create reusable custom validators by defining them as separate classes and then using them in different models.