Can't retrieve claims added after login

Question

I need to temporarily add certain claims to the user, the value of which can change and hence I need to add those claims only when a user successfully logs in. But when I search for this claim in HttpContext.User, it's not there. I can't figure out what I'm doing wrong. Here is my login controller.

EDIT: Using ASP.NET Core 1.0, and ASP.NET Identity. Not using Identity Server.

public async Task<IActionResult> Login(LoginIdentityModel lim)
{
    var user = await _userManager.FindByEmailAsync(lim.username);
    if (user != null)
    {
        Claim c = new Claim("ProductUploadRequest", "Allow");
        await _userManager.AddClaimAsync(user, c);
        var result = await _signInManager.PasswordSignInAsync(user, lim.password, false, lockoutOnFailure: false);
        if (result.Succeeded)
        {
             var usr = HttpContext.User;//claim not found here
        }
}

Answer 1

According to this discussion, HttpContext.User isn't updated by a SignIn call and it is by design:

Normally the ClaimsPrincipal is only modified with the result of sign in for the next request when it returns with the Cookie.

As a workaround to retrieve the claims immediately, try:

_userManager.GetClaimsAsync(user);