ASP.NET Core Web API - FluentValidationMvcExtensions.AddFluentValidation(IMvcBuilder, Action<FluentValidationMvcConfiguration>)' is obsolete

Question

In ASP.NET Core-6 Web API, I am using FluentValidation.AspNetCore(11.2.1).

I have this code in the Program.cs:

builder.Services.AddMvc().AddFluentValidation(fv => {
    fv.DisableDataAnnotationsValidation = true;
    fv.RegisterValidatorsFromAssembly(typeof(Program).Assembly);
    fv.RegisterValidatorsFromAssembly(Assembly.GetExecutingAssembly());
    fv.ImplicitlyValidateChildProperties = true;
    fv.ImplicitlyValidateRootCollectionElements = true;
    fv.AutomaticValidationEnabled = true;
});

But I got this error with all the code above highlighted:

FluentValidationMvcExtensions.AddFluentValidation(IMvcBuilder, Action)' is obsolete: 'Calling AddFluentValidation() is deprecated

How do I get this resolved?

Thanks

Answer 1

As per the documentation (https://docs.fluentvalidation.net/en/latest/aspnet.html) it is not recommended to use Automatic validation.

So I will recommend to not use Automatic Validation and remove the AddMvc() because automatic validation works with AddMvc, https://github.com/FluentValidation/FluentValidation/issues/1377

Now Let's come to your problem, assuming you are using .net6, following code should work.

using FluentValidation.AspNetCore;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddFluentValidation(conf =>
{
 conf.RegisterValidatorsFromAssembly(typeof(Program).Assembly);
 conf.AutomaticValidationEnabled = false;
});