using System;

using System.Linq;

​

namespace Blah

{

    public class Program

    {

        public static void Main(string[] args)

        {

            User[] myUsers = new User[]{

                new User("A1", 1, true),

                new User("B1", 1, false),

                new User("C3", 3, true),

                new User("D5", 5, false),

                new User("E6", 6, true),

                new User("F20", 20, true)

            };

​

            PerfLoc[] myPerfLocs = new PerfLoc[]{

                new PerfLoc(1),

                new PerfLoc(2),

                new PerfLoc(3),

                new PerfLoc(4),

                new PerfLoc(5),

                new PerfLoc(6)

            };

​

            // to test not passing any PerfLocs

            myPerfLocs = new PerfLoc[] { };

​

            bool checkActive = true;

​

            // set up result list - variable needs to be IEnumerable<User>, not List<User>

            var filteredUser = myUsers.AsEnumerable();

​

            // add Active check if necessary

            if (checkActive)

            {

                filteredUser = filteredUser.Where(u => u.Active);

            }

​

            // check against PerfLoc list if necessary

            if (myPerfLocs.Any())

            {

                filteredUser = from u in filteredUser

                               join p in myPerfLocs on u.PerfLoc equals p.Number.ToString()

                               select u;

            }

​

            filteredUser = filteredUser.OrderBy(u => u); // or u => u.Name etc if you want

​

            foreach (User match in filteredUser)

            {

                Console.WriteLine(match.Name);

            }

        }

    }

​

    public class User : IComparable

    {

        // some properties

        public string Name { get; set; }

        public string PerfLoc { get; set; }

        public bool Active { get; set; }

        // constructor would follow ..

        public User(string n, int p, bool a)

        {

            this.Name = n;

            this.PerfLoc = p.ToString();

            this.Active = a;

        }

​

        public int CompareTo(object obj)

        {

            return this.Name.CompareTo(((User)obj).Name);

        }

    }

​

    public class PerfLoc

    {

        // some properties

        public int Number { get; set; }

        // constructor would follow ..

        public PerfLoc(int num)

        {

            this.Number = num;

        }

    }

}

​