Nedo.AspNet.Common.Validation.Core 1.9.1

Nedo.AspNet.Common.Validation.Core

Core validation engine for .NET 9 with 120+ built-in validators across 12 categories, full localization support, and a composable IValidator<T> pipeline.

Install

dotnet add package Nedo.AspNet.Common.Validation.Core

Key Components

Quick Start

Static Validator Calls

Each validator is a static method returning ValidationError? — null means the value is valid.

using Nedo.AspNet.Common.Validation.Core.Validators.Generic;
using Nedo.AspNet.Common.Validation.Core.Validators.String;
using Nedo.AspNet.Common.Validation.Core.Validators.Numeric;

// Single check
var error = MinLengthValidator.Validate(
    value: userName,
    fieldName: "Name",
    minLength: 5,
    cultureName: "en");

if (error != null)
    Console.WriteLine($"[{error.Code}] {error.Message}");

Collecting Multiple Errors

using Nedo.AspNet.Common.Validation.Core;
using Nedo.AspNet.Common.Validation.Core.Contracts;

var errors = new List<ValidationError>();
errors.AddIfNotNull(RequiredValidator.Validate(user.Name, "Name", "en"));
errors.AddIfNotNull(MinLengthValidator.Validate(user.Name, "Name", 5, "en"));
errors.AddIfNotNull(AlphaValidator.Validate(user.Name, "Name", "en"));
errors.AddIfNotNull(RequiredValidator.Validate(user.Email, "Email", "en"));

var result = errors.Count == 0
    ? ValidationResult.Success
    : new ValidationResult(errors);

CompositeValidator

Compose multiple IValidator<T> instances and/or inline delegates into one:

using Nedo.AspNet.Common.Validation.Core;

var composite = new CompositeValidator<UserDto>()
    .Add(existingValidator)                       // Any IValidator<UserDto>
    .Add((dto, culture) =>                        // Inline rule
        RequiredValidator.Validate(dto.Name, "Name", culture ?? "en"))
    .Add((dto, culture) =>
        MinLengthValidator.Validate(dto.Name, "Name", 3, culture ?? "en"));

var result = composite.Validate(dto, "id");

Merging Results

var merged = ValidationResultExtensions.Merge(result1, result2, result3);

Localization

All validators accept a cultureName parameter. Built-in .resx files provide messages in:

• English (en) — default
• Indonesian (id)

Adding a New Language

1. Create ValidationMessages.<lang>.resx (e.g. ValidationMessages.fr.resx)
2. Provide translated values keyed by message name
3. Deploy the satellite assembly alongside the library

// Messages are automatically resolved by cultureName parameter
var error = RequiredValidator.Validate(null, "Name", "id");
// → "Kolom Name wajib diisi."

var errorEn = RequiredValidator.Validate(null, "Name", "en");
// → "The field Name is required."

Validator Catalog

Generic Validators

String Validators

Numeric Validators

Date Validators

DateTime / Time Validators

File Validators

Image Validators

IP Address Validators

URL Validators

UUID Validators

Phone Validators

Location Validators

Money Validators

Validator Method Signature

All validators follow the same pattern:

public static ValidationError? Validate(
    <TValue> value,       // The value to validate
    string fieldName,     // Member name for error reporting
    <TParam> param,       // Optional: validator-specific parameter (minLength, pattern, etc.)
    string cultureName)   // Language for error messages ("en", "id", etc.)

• Returns null if valid
• Returns ValidationError if invalid
• Returns null for null values (except RequiredValidator) — delegates null checks to RequiredValidator

Related Packages

• Nedo.AspNet.Common.Validation.Fluent — Fluent AbstractValidator<T> API with chained rules
• Nedo.AspNet.Common.Validation.Dsl — Text-based DSL for runtime rule definitions