Get value from cliams table

Question

Hello evey one how to get value from Claims Table in .net core. I have try to this code but null value face 

 ClaimsPrincipal p = this.User;
                            var r = p.Identities.ToList();
                            if (r[0].FindFirst(c => c.Type == "ID") != null)
                            {
                                var IDs = data[0].FindFirst(c => c.Type == "ID").Value;
                            }