Unable to resolve service for type 'Microsoft.AspNetCore.Identity.UserManager hile attempting to activate 'Controllers.AccountsController'

Question

I have the following code in the AccountsController :

using System.Threading.Tasks;
using AutoMapper;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;
using Products.Helpers;
using Products.Models;
using Products.ViewModels;

namespace Products.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class AccountsController : Controller
    {
        private readonly ContextUsers _appDbContext;
        private readonly UserManager<AppUser> _userManager;
        private readonly IMapper _mapper;

    public AccountsController(ContextUsers context,UserManager<AppUser> userManager,IMapper mapper)
    {
        _appDbContext = context;
        _userManager = userManager;
        _mapper = mapper;
    }


    [HttpPost]
    public async Task<IActionResult> Post([FromBody]RegistrationViewModel model)
    {
        if (!ModelState.IsValid)
        {
            return BadRequest(ModelState);
        }

        var userIdentity = _mapper.Map<AppUser>(model);

        var result = await _userManager.CreateAsync(userIdentity, model.Password);

        if (!result.Succeeded) return new BadRequestObjectResult(Errors.AddErrorsToModelState(result, ModelState));

        await _appDbContext.Customers.AddAsync(new Customer { IdentityId = userIdentity.Id, Location = model.Location });
        await _appDbContext.SaveChangesAsync();
        return new OkObjectResult("Account created");
    }
}

}

And I have the following code in the AppUser class:

public class AppUser : IdentityUser
{
  // Extended Properties
  public string FirstName { get; set; }
  public string LastName { get; set; }
  public long? FacebookId { get; set; }
  public string PictureUrl { get; set; }
}

And the following Customer class:

public class Customer
{
 public int Id { get; set; }
 public string IdentityId { get; set; }
 public AppUser Identity { get; set; }  // navigation property
 public string Location { get; set; }
 public string Locale { get; set; }
 public string Gender { get; set; }
}

When i make a post request in postman i get the following error:

InvalidOperationException: Unable to resolve service for type 'Microsoft.AspNetCore.Identity.UserManager`1[Products.Models.AppUser]' while attempting to activate 'Products.Controllers.AccountsController'.
Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetService(IServiceProvider sp, Type type, Type requiredBy, bool isDefaultParameterRequired)

I am trying to create a user but when I make the post request doesn't even enter the controller so I can't debug

ConfigureServices method from startup.cs:

public void ConfigureServices(IServiceCollection services)
        {

                .AddCors(o => o.AddPolicy("AllowAllOrigins", builder =>
            {
                builder.AllowAnyMethod()
                    .AllowAnyHeader()
                    .AllowAnyOrigin();
            }));

            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);

            services.AddDbContext<Context>(options =>
                    options.UseSqlServer(Configuration.GetConnectionString("LaprDB")));
            services.AddDbContext<ContextUsers>(options =>
                options.UseSqlServer(Configuration.GetConnectionString("MyDbConnection")));


            services.AddHostedService<TimedHostedService>();

             services.AddAutoMapper();


        }

Answer 1

You are missing a line to add the Identity object to the DI container. You need to call the AddDefaultIdentity method. Add this line to the ConfigureServices method in your Startup class:

services.AddDefaultIdentity<AppUser>()
    .AddEntityFrameworkStores<ContextUsers>();

See here for more information on setting up Identity.