using System;

using System.DirectoryServices.AccountManagement;

​

public class AuthenticationService

{

    public bool AuthenticateUser(string username, string password)

    {

        try

        {

            // Replace with your actual AD domain

            string domain = "corp.example.com";

​

            // ContextType can be Domain, ApplicationDirectory, or Machine

            using (PrincipalContext pc = new PrincipalContext(ContextType.Domain, domain))

            {

                // Validate the credentials

                return pc.ValidateCredentials(username, password);

            }

        }

        catch

        {

            // Catch any exceptions during authentication and return false

            return false;

        }

    }

    public static void Main(string[] args)

    {

         AuthenticationService authService = new AuthenticationService();

​

        // Simulate AD user.  In real implementation, these would be actual AD users.

        //For testing purposes these credential would exists in AD

        string username = "validuser";

        string password = "validpassword";

​

​

        // Act

        bool result = authService.AuthenticateUser(username, password);

        Console.WriteLine(result);

​

    }

}

​