Validation

QuickForm has two types of validation

• DataAnnotationsValidator
• Blazored.FluentValidationValidator

Both of which can be disabled with setting EnableDataAnnotationsValidation and EnableFluentValidation parameters to false.

DataAnnotationAttributes

public class User
{
    [Required]
    public string Name { get; set; }

    [Range(18, 100. ErrorMessage = "You must be 18 years or older to register")]
    public int Age { get; set; }

    [RegularExpression(@"^(?=.*[a-z])(?=.*[A-Z]).{8,32}$", ErrorMessage = "Password must have at least 8 characters, one uppercase letter, one lowercase letter...")]
    public string Password { get; set; }
}

FluentValidation

public class ProductCreateCommand
{
    public string Name { get; set; }

    public decimal Price { get; set; }
}

public class ProductCreateCommandValidator : AbstractValidator<ProductCreateCommand>
{
    public ProductCreateCommandValidator(IProductRepository productRepository)
    {
        RuleFor(x => x.Name)
            .NotEmpty()
            .WithMessage("Name is required")
            .MustAsync(async (name, product, cancellationToken) => {
                var product = await productRepository.GetByNameAsync(name, cancellationToken);
                return product is null;
            })
            .WithMessage("Product with this name already exists");

        RuleFor(x => x.Price)
            .GreaterThan(0)
            .WithMessage("Price must be greater than 0");
    }
}

Info

These validation rules will be automatically applied to your form, all fields will get validated when they are changed.