Wrong ID user - ASP NET CORE

Question

I am using ASP.NET CORE 2.0, and am having to catch the logged-in user ID. This is my Account Controller:

[Route("[controller]/[action]")]
public class AccountController : Controller
{
    private readonly SignInManager<ApplicationUser> _signInManager;
    private readonly ILogger _logger;
    private readonly UserManager<ApplicationUser> _userManager;

    public AccountController(SignInManager<ApplicationUser> signInManager, ILogger<AccountController> logger, UserManager<ApplicationUser> userManager)
    {
        _signInManager = signInManager;
        _logger = logger;
        _userManager = userManager;
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> Logout()
    {
        await _signInManager.SignOutAsync();
        _logger.LogInformation("User logged out.");
        return RedirectToPage("./Index");
    }
}

I'm trying to get the id this way:

ApplicationUser a = new ApplicationUser();
        CR.FuncionarioId =  a.Id;

But he's returning me a completely different id, why is this happening? I use Identity. Then when I use a.Id, every hour I immediately, even though it is with the same user, it brings a different Id, and it is not bringing the Id that is registered in the AspnetUsers table.

code of the page where I need to get the user id:

protected UserManager<ApplicationUser> UserManager { get; set; }
    public RecebimentoModel(CronoParque.Model.ApplicationDbContext context)
    {
        _context = context;
    }
    [BindProperty]
    public string Message { get; set; }
    [BindProperty]
    public ContasReceberViewModel ContasReceberVM { get; set; }



    public async Task<IActionResult> OnPost()
    {
        if (ModelState.IsValid)
        {
            var CR = _context.ContasReceber.Find(ContasReceberVM.ContasReceber.Id);
            CR.Quitado = true;
            CR.ValorPago = Convert.ToDecimal(ContasReceberVM.ContasReceber.ValorPago.ToString().Replace(",","."));
            CR.FormaPagamento = ContasReceberVM.ContasReceber.FormaPagamento;
            CR.DataPagamento = DateTime.Now;
            CR.FuncionarioId = UserManager.GetUserId(HttpContext.User);
            await _context.SaveChangesAsync();
            Message = "Pagamento Realizado com Sucesso!";

            return RedirectToPage("Index");
        }
        return RedirectToPage();
    }

Answer 1

var user = _userManager.GetUserAsync(User);
var id = user.Result.Id;

try this in your function, it should work :)