Get Microsoft Identity value/type?

Question

ASP.NET

I am using library ClaimsIdentity in Asp.net for user authentication.

var claims = new List<Claim>
                {
                    new Claim(ClaimsIdentity.DefaultNameClaimType, loginModel.NickName),
                    new Claim(ClaimsIdentity.DefaultRoleClaimType, loginModel.UserRole),
                    new Claim("UserID", loginModel.UserId.ToString()),
                };
                ClaimsIdentity claimsIdentity = new ClaimsIdentity(
                    claims,
                    "ApplicationCookie",
                    ClaimsIdentity.DefaultNameClaimType,
                    ClaimsIdentity.DefaultRoleClaimType);

In the future, I can use enclosing helpers in controllers, for example

[Authorize(Roles = "administrator")]
public IActionResult Index() { //to do
}

The question is the following. How can I get the same key/value from the cookie.DefaultRoleClaimType from the HttpContext, for example?

Thank you!