FluentAnnotationsValidator 1.2.2

FluentAnnotationsValidator

A fluent, type-safe validation engine for .NET that transforms [ValidationAttribute] annotations into runtime validation logic. Supports conditional rules, culture-scoped messages, and discoverable configuration via DSL.

Features

• Automatic validation from [Required], [Range], [EmailAddress], etc.
• Culture-aware localization from .resx or static resource classes
• Conditional logic per property via .When(...), .Localized(...), .UseFallbackMessage(...)
• Implicit rule generation based on global config (.WithCulture(...), .WithValidationResource(...))
• Smooth integration with ASP.NET and IValidator<T>
• DSL configuration: target types, cultures, resource mapping, conventions

Quick Setup

Fluent Validation Configuration

Start with automatic rule generation via [ValidationAttribute], then layer culture and localization resources:

using FluentAnnotationsValidator.Extensions;
using System.Globalization;

services.AddFluentAnnotationsValidators(typeof(LoginDto))
    .UseFluentAnnotations()
    .For<LoginDto>()
        .WithCulture(CultureInfo.GetCultureInfo("fr-FR"))
        .WithValidationResource<ValidationMessages>() // Scoped .resx lookup
    .Build();

Or inject conditional validation logic with localized error fallback:

services.UseFluentAnnotations()
    .For<LoginDto>()
        .WithCulture(CultureInfo.GetCultureInfo("fr-FR"))
        .WithValidationResource<ValidationMessages>()
        .When(x => x.Password, dto => string.IsNullOrEmpty(dto.Password))
            .Localized("Password_Required") // Looks up ValidationMessages.Password_Required
            .UseFallbackMessage("Mot de passe requis.") // Fallback if resource key is missing
    .Build();

⚠️ Heads-up: Current version supports only one rule per property.
If a property has multiple [ValidationAttribute]s, only the last one will be processed.
This will be resolved in v2.0.0 with full multi-attribute resolution.

v1.2.2 Highlights

• Fixed implicit rule synthesis for attributes lacking .When(...)
• Respects global culture and resource bindings during fallback
• Improved configurator registry architecture for future rule aggregation
• Warning added for multi-attribute scenarios pending v2.0.0 release

Installation

dotnet add package FluentAnnotationsValidator --version 1.2.2

Test Coverage

• ✅ [Required], [EmailAddress], [MinLength], [Range] support
• ✅ Localized message binding from culture+resource
• ✅ Fallback behavior for .Build() without manual rule definitions

Learn More

• GitHub Repository
• NuGet Package

Highlights

• WithCulture(...) binds CultureInfo globally across rules for this type.
• WithValidationResource<T>() uses .resx-backed messages with safe fallback.
• When(...) applies targeted conditions with fluent chaining for per-property logic.
• Localized(...) uses string keys like "Email_Required", typically mapped to ValidationMessages resource entries.

Documentation

See configuration guide for advanced usage.

Contribute

Open to feedback, extensions, and collaboration - shape validation ergonomics for developers worldwide.