Csharp/C Sharp/Windows/Windows Principal

Get Current Windows Identity

using System;
using System.Security.Principal;
class MainClass {
    public static void Main(string[] args) {
        WindowsIdentity identity = WindowsIdentity.GetCurrent();
        WindowsPrincipal principal = new WindowsPrincipal(identity);
        foreach (string role in args) {
            Console.WriteLine("Is {0} a member of {1}? = {2}",
             identity.Name, role, principal.IsInRole(role));
        }
    }
}

Use Properties of WindowsPrincipal

using System;
using System.Security.Principal;
using System.Security.Permissions;
using System.Threading;
class Program {
    static void Main(string[] args) {
        AppDomain.CurrentDomain.SetPrincipalPolicy(PrincipalPolicy.WindowsPrincipal);
        WindowsPrincipal principal = (WindowsPrincipal)Thread.CurrentPrincipal;
        WindowsIdentity identity = (WindowsIdentity)principal.Identity;
        Console.WriteLine("IdentityType: " + identity.ToString());
        Console.WriteLine("Name: " + identity.Name);
        Console.WriteLine(""Users"?: " + principal.IsInRole("BUILTIN\\Users"));
        Console.WriteLine(""Administrators"?: " + principal.IsInRole(WindowsBuiltInRole.Administrator));
        Console.WriteLine("Authenticated: " + identity.IsAuthenticated);
        Console.WriteLine("AuthType: " + identity.AuthenticationType);
        Console.WriteLine("Anonymous?: " + identity.IsAnonymous);
        Console.WriteLine("Token: " + identity.Token);
    }
}

WindowsBuiltInRole.Administrator

using System;
using System.Security.Principal;
class Class1
{
    static void Main()
  {   
    WindowsIdentity wi = WindowsIdentity.GetCurrent();
    WindowsPrincipal wp = new WindowsPrincipal(wi);
        if (wp.IsInRole(WindowsBuiltInRole.Administrator))
      Console.WriteLine("Your are an Administrator!");
    else
      Console.WriteLine("You are not an Administrator.");
    if (wp.IsInRole("POWERHOUSE\\Developer"))
      Console.WriteLine("You are in the Developer group!");
    else
      Console.WriteLine("You are not in the Developer group.");
  }
}

WindowsImpersonationContext

using System;
using System.IO;
using System.Security.Principal;
using System.Security.Permissions;
using System.Runtime.InteropServices;
[assembly: SecurityPermission(SecurityAction.RequestMinimum, UnmanagedCode = true, ControlPrincipal = true)]
class MainClass {
    const int LOGON32_PROVIDER_DEFAULT = 0;
    const int LOGON32_LOGON_INTERACTIVE = 2;
    [DllImport("advapi32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
    static extern bool LogonUser(string userName, string domain,
        string password, int logonType, int logonProvider,
        ref IntPtr accessToken);
    public static void Main(string[] args) {
        IntPtr accessToken = IntPtr.Zero;
        bool success = LogonUser(
            args[0],                    // username to log on.
            ".",                         // use the local account database.
            args[1],                    // user"s password.
            LOGON32_LOGON_INTERACTIVE,  // create an interactive login.
            LOGON32_PROVIDER_DEFAULT,    // use the default logon provider.
            ref accessToken             // receives access token handle.
        );
        if (!success) {
            Console.WriteLine("LogonUser returned error {0}",
               Marshal.GetLastWin32Error());
        } else {
            WindowsIdentity identity = new WindowsIdentity(accessToken);
            Console.WriteLine(WindowsIdentity.GetCurrent().Name);
            WindowsImpersonationContext impContext = identity.Impersonate();
            Console.WriteLine(WindowsIdentity.GetCurrent().Name);
            impContext.Undo();
            Console.WriteLine(WindowsIdentity.GetCurrent().Name);
        }
    }
}

WindowsPrincipal Enables You to Check for Role Membership

using System;
using System.Security.Principal;
   
class Class1 {
    static void Main() {   
       WindowsIdentity wi = WindowsIdentity.GetCurrent();
       WindowsPrincipal wp = new WindowsPrincipal(wi);
   
       // This checks for local administrator rights if you in a Domain
       if (wp.IsInRole(WindowsBuiltInRole.Administrator))
           Console.WriteLine("Your are an Administrator!");
       else
           Console.WriteLine("You are not an Administrator.");
   
       if (wp.IsInRole("YourRole\\Developer"))
           Console.WriteLine("You are in the Developer group!");
       else
           Console.WriteLine("You are not in the Developer group.");
  }
}

WindowsPrincipal.IsInRole

using System;
using System.Security.Principal;
class MainClass {
    public static void Main(string[] args) {
        WindowsIdentity identity = WindowsIdentity.GetCurrent();
        WindowsPrincipal principal = new WindowsPrincipal(identity);
        foreach (string role in args) {
            Console.WriteLine("Is {0} a member of {1}? = {2}",
             identity.Name, role, principal.IsInRole(role));
        }
    }
}