fluent validator in class library not work in asp.net core

Question

when i put fluent validators in asp.net core client side validation project exactly work but when i put validator in class library not work

My model and validator in class library :

using FluentValidation;

namespace ClassLibrary1
{
    public class Person
    {
        public string Name { get; set; }
        public string Family { get; set; }
        public int Age { get; set; }
    }
    public class PersonValidator : AbstractValidator<Person>
    {
        public PersonValidator()
        {
            RuleFor(c => c.Name).NotEmpty().WithMessage("Name Is Empty");

        }
    }
}

In program.cs file :

services.AddFluentValidationAutoValidation(M =>
{
    M.DisableDataAnnotationsValidation = true;
}).AddFluentValidationClientsideAdapters()
  .AddValidatorsFromAssemblyContaining<PersonValidator>();

Answer 1

I can't reproduce the issue, and it works in my side, I will show my test steps.

Steps

1. my project structure.

   

2. The person.cs code same as yours

   

3. The program.cs code same as yours

   

4. My test method in Controller.

    [HttpPost]
    [Route("Test")]
    public IActionResult Test([FromBody]Person model)
    {
        if (!ModelState.IsValid) //<----Validate here
        {
            return new BadRequestObjectResult(ModelState);
        }
        return Ok();
        //Other Code..
    }
   

5. Test result and it works.

   

Answer 2

I found the solution.

When the class library is nullable, the client-side validation in ASP.NET Core does not work.

Solution:

1. Remove <Nullable>enable</Nullable> from the *.csproj

2. Define nullable property:

   public string? name{get;set}