官网：https://docs.fluentvalidation.net/en/latest/index.html

入门程序

安装

使用 Visual Studio 中的 NuGet 包管理器控制台运行以下命令：

Install-Package FluentValidation

或者从终端窗口使用 .net core CLI：

dotnet add package FluentValidation

案例：登录

编写通用返回类

namespace FluentValidationTest
{
    public class Result
    {
        public string Message { get; set; }

        public int Code { get; set; }

        public dynamic Data { get; set; }

        public static Result Success(dynamic data = null)
        {
            Result result = new Result();
            result.Data = data;
            result.Code = 1;
            result.Message = "success.";
            return result;
        }

        public static Result Fail(string message)
        {
            Result result = new Result();
            result.Code = 0;
            result.Message = message;
            return result;
        }
    }
}

编写登录请求类

using System.ComponentModel;

namespace FluentValidationTest
{
    public class LoginRequest
    {
        [Description("用户名")]
        public string UserName { get; set; }

        [Description("密码")]
        public string Password { get; set; }
    }
}

编写登录请求验证类

using FluentValidation;

namespace FluentValidationTest
{
    public class LoginRequestValidator : AbstractValidator<LoginRequest>
    {
        public LoginRequestValidator()
        {
            RuleFor(x => x.UserName).NotEmpty().WithMessage("用户名不能为空");
            RuleFor(x => x.Password).NotEmpty().WithMessage("密码不能为空");
            RuleFor(x => x.Password).MinimumLength(6).MaximumLength(20).WithErrorCode("-200").WithMessage("密码长度在6-20");
        }
    }
}

编写用户控制器

using FluentValidation.Results;
using Microsoft.AspNetCore.Mvc;

namespace FluentValidationTest.Controllers
{
    [ApiController]
    [Route("[controller]/[action]")]
    public class UserController : ControllerBase
    {
        [HttpPost]
        public async Task<Result> Login(LoginRequest request)
        {
            LoginRequestValidator validations = new LoginRequestValidator();
            //验证
            ValidationResult validationResult = validations.Validate(request);
            if (!validationResult.IsValid)
            {
                return Result.Fail(validationResult.Errors[0].ErrorMessage);
            }
            return Result.Success();
        }
    }
}

测试

验证器

内置验证器

网站：https://docs.fluentvalidation.net/en/latest/built-in-validators.html

• NotNull Validator
• NotEmpty Validator
• NotEqual Validator
• Equal Validator
• Length Validator
• MaxLength Validator
• MinLength Validator
• Less Than Validator
• Less Than Or Equal Validator
• Greater Than Validator
• Greater Than Or Equal Validator
• Predicate Validator
• Regular Expression Validator
• Email Validator
• Credit Card Validator
• Enum Validator
• Enum Name Validator
• Empty Validator
• Null Validator
• ExclusiveBetween Validator
• InclusiveBetween Validator
• PrecisionScale Validator

自定义验证器

编写自定义验证器

            RuleFor(x => x.UserName).Custom((userName, context) =>
            {
                if (!userName.Contains("admin"))
                {
                    context.AddFailure("not amdin.");
                }
            });

可重复使用的属性验证器

在某些情况下，您的自定义逻辑非常复杂，您可能希望将自定义逻辑移至单独的类中。这可以通过编写一个继承抽象类的类来完成 PropertyValidator<T,TProperty>（这是 FluentValidation 的所有内置规则的定义方式）。

using FluentValidation.Validators;
using FluentValidation;

namespace FluentValidationTest
{
    /// <summary>
    /// 条件验证器
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <typeparam name="TProperty"></typeparam>
    public class ConditionValidator<T, TProperty> : PropertyValidator<T, TProperty>
    {
        Func<T, TProperty, bool> _func;

        string _message;

        /// <summary>
        ///
        /// </summary>
        /// <param name="func">委托</param>
        /// <param name="message">提示消息</param>
        public ConditionValidator(Func<T, TProperty, bool> func, string message)
        {
            _func = func;
            _message = message;
        }

        public override string Name => "ConditionValidator";

        public override bool IsValid(ValidationContext<T> context, TProperty value)
        {
            return _func.Invoke(context.InstanceToValidate, value);
        }

        protected override string GetDefaultMessageTemplate(string errorCode)
          => _message;
    }

    /// <summary>
    /// 扩展类
    /// </summary>
    public static class ValidatorExtensions
    {
        public static IRuleBuilderOptions<T, TElement> Condition<T, TElement>(this IRuleBuilder<T, TElement> ruleBuilder, Func<T, TElement, bool> func, string message)
        {
            return ruleBuilder.SetValidator(new ConditionValidator<T, TElement>(func, message));
        }
    }
}

使用

 RuleFor(x => x.UserName).Condition((a, b) => a.UserName.Contains("admin"),"不符合条件");

本地化

如果您想替换 FluentValidation 的全部（或部分）默认消息，则可以通过实现接口的自定义版本来实现 ILanguageManager。

例如，NotNull 验证器的默认消息是。如果您想为应用程序中验证器的所有使用替换此消息，您可以编写一个自定义语言管理器：‘{PropertyName}’ must not be empty.

using FluentValidation.Resources;
using FluentValidation.Validators;

namespace FluentValidationTest
{
    public class CustomLanguageManager : LanguageManager
    {
        public CustomLanguageManager()
        {
            AddTranslation("en", "NotEmptyValidator", "{PropertyName} 值为空");
            AddTranslation("en", "MinimumLengthValidator", "{PropertyName} {PropertyValue} 小于 {MinLength}");
        }

    }
}

Program 类

ValidatorOptions.Global.LanguageManager = new CustomLanguageManager();

DI

https://docs.fluentvalidation.net/en/latest/di.html

Install-Package FluentValidation.DependencyInjectionExtensions

Program.cs添加

            builder.Services.AddValidatorsFromAssemblyContaining<LoginRequestValidator>();
            //builder.Services.AddValidatorsFromAssembly(Assembly.Load("FluentValidationTest"));

控制器实现

    public class UserController : ControllerBase
    {
        private LoginRequestValidator _loginRequestValidator;
        public UserController(LoginRequestValidator loginRequestValidator)
        {
            _loginRequestValidator = loginRequestValidator;
        }
    }

自动验证

https://github.com/SharpGrip/FluentValidation.AutoValidation

安装 nuget 包

Install-Package SharpGrip.FluentValidation.AutoValidation.Mvc

配置

using SharpGrip.FluentValidation.AutoValidation.Mvc.Extensions;

builder.Services.AddFluentValidationAutoValidation(configuration =>
{
    // Disable the built-in .NET model (data annotations) validation.
    configuration.DisableBuiltInModelValidation = true;

    // Only validate controllers decorated with the `FluentValidationAutoValidation` attribute.
    configuration.ValidationStrategy = ValidationStrategy.Annotation;

    // Enable validation for parameters bound from `BindingSource.Body` binding sources.
    configuration.EnableBodyBindingSourceAutomaticValidation = true;

    // Enable validation for parameters bound from `BindingSource.Form` binding sources.
    configuration.EnableFormBindingSourceAutomaticValidation = true;

    // Enable validation for parameters bound from `BindingSource.Query` binding sources.
    configuration.EnableQueryBindingSourceAutomaticValidation = true;

    // Enable validation for parameters bound from `BindingSource.Path` binding sources.
    configuration.EnablePathBindingSourceAutomaticValidation = true;

    // Enable validation for parameters bound from 'BindingSource.Custom' binding sources.
    configuration.EnableCustomBindingSourceAutomaticValidation = true;

    // Replace the default result factory with a custom implementation.
    configuration.OverrideDefaultResultFactoryWith<CustomResultFactory>();
});

自定义返回结果

using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Filters;
using SharpGrip.FluentValidation.AutoValidation.Mvc.Results;

namespace FluentValidationTest
{
    public class CustomResultFactory : IFluentValidationAutoValidationResultFactory
    {
        public IActionResult CreateActionResult(ActionExecutingContext context, ValidationProblemDetails? validationProblemDetails)
        {
            return new JsonResult(Result.Fail(validationProblemDetails.Errors.Values.FirstOrDefault()[0]));
        }
    }
}