C# 声明基于角色的安全性

using System;
using System.Collections.Generic;
using System.Linq;
using System.Security;
using System.Security.Permissions;
using System.Security.Principal;
using System.Text;
using System.Threading;
using System.Threading.Tasks;


namespace Exam2
{
    class Program
    {
        static void Main(string[] args)
        {
            AppDomain.CurrentDomain.SetPrincipalPolicy(PrincipalPolicy.WindowsPrincipal);
            try
            {
                ShowMessage();
            }
            catch (SecurityException exception)
            {
                Console.WriteLine("Security exception caught ({0})", exception.Message);
                Console.WriteLine("The current principal must be in the local"
                                  + "Users group");
            }


            Console.Read();
        }
        //[PrincipalPermission(SecurityAction.Demand, Role = "BUILTIN\\Users")]
        [PrincipalPermission(SecurityAction.Demand, Role = "BUILTIN\\Guest")]
        static void ShowMessage()
        {
            Console.WriteLine("The current principal is logged in locally ");
            Console.WriteLine("(member of the local Users group)");
        }
    }
}