System Security Principal C# by API

using System;
using System.Threading;
using System.Collections.Generic;
using System.IO;
using System.IO.IsolatedStorage;
using System.Net;
using System.Net.Sockets;
using System.Reflection;
using System.Security;
using System.Security.AccessControl;
using System.Security.Policy;
using System.Security.Permissions;
using System.Security.Principal;
using System.Text;
public class MainClass
{
    public static void Main()
    {
        IPrincipal user = Thread.CurrentPrincipal;
        if (!user.IsInRole("Administrators"))
            Console.WriteLine("User not in the 'admin' role");
        else
            Console.WriteLine("User is an 'admin'");
    }
}