using System;

using System.Collections.Generic;

using System.Linq;

using System.Linq.Expressions;

public class Program

{

    public static void Main()

    {

        var people = GetPeople();       

        ConsolePeople(GetPeopleFiltered(GetFilters(new FilterRequest {Male = true}), people));

        ConsolePeople(GetPeopleFiltered(GetFilters(new FilterRequest {Female= true}), people));

        ConsolePeople(GetPeopleFiltered(GetFilters(new FilterRequest {Male = true, TwentyToThirty = true}),people));

        ConsolePeople(GetPeopleFiltered(GetFilters(new FilterRequest {Male = true, Female=true, TwentyToThirty = true}),people));

    }

    public static void ConsolePeople(List<Person> people)

    {

        if(people.Count == 0)

            Console.WriteLine("No people found");

        foreach(var person in people)

        {

            Console.WriteLine(string.Format("FirstName: {0}, LastName: {1}, Age: {2}, Gender: {3}", person.FirstName, person.LastName, person.Age, person.Gender.ToString()));

        }

        Console.WriteLine(string.Empty);

    }

    public static List<Person> GetPeople()

    {

        var people = new List<Person>();

        people.Add(new Person { FirstName = "Philip", LastName = "Smith", Age = 29, Gender = GenderEnum.Male});

        people.Add(new Person { FirstName = "Joe", LastName = "Blogs", Age = 40, Gender = GenderEnum.Male});        

        people.Add(new Person { FirstName = "Mary", LastName = "Ann", Age = 10, Gender = GenderEnum.Female});

        people.Add(new Person { FirstName = "Lisa", LastName = "Dunn", Age = 60, Gender = GenderEnum.Male});

        people.Add(new Person { FirstName = "Terry", LastName = "Banks", Age = 89, Gender = GenderEnum.Male});

        people.Add(new Person { FirstName = "John", LastName = "Doe", Age = 32, Gender = GenderEnum.Male});

        people.Add(new Person { FirstName = "Sally", LastName = "Shields", Age = 19, Gender = GenderEnum.Female});

        return people;

    }

    public static List<Expression<Func<Person, bool>>> GetFilters(FilterRequest request)

    {

        var filters = new List<Expression<Func<Person, bool>>>();

        if(request.Male)

            filters.Add(x=>x.Gender == GenderEnum.Male);

        if(request.Female)

            filters.Add(x=>x.Gender == GenderEnum.Female);

        if(request.TentoTwenty)

            filters.Add(x=>x.Age >= 10 && x.Age < 20);

        if(request.TwentyToThirty)

            filters.Add(x=>x.Age >= 20 && x.Age < 30);

        if(request.ThirtyToFourty)

            filters.Add(x=>x.Age >= 30 && x.Age < 40);

        if(request.FourtyPlus)

            filters.Add(x=>x.Age >= 40);

        return filters;

    }

    public static List<Person> GetPeopleFiltered(List<Expression<Func<Person,bool>>> filters, List<Person> people)

    {

        var query = people.AsQueryable();

        foreach(var filter in filters)

        {

            query = query.Where(filter);

        }

        return query.ToList();

    }

}

​

public class FilterRequest

{

    public bool Male {get;set;}

    public bool Female {get;set;}

    public bool TentoTwenty {get;set;}

    public bool TwentyToThirty {get;set;}

    public bool ThirtyToFourty {get;set;}

    public bool FourtyPlus {get;set;}

}

​

public class Person

{

    public string FirstName {get;set;}

    public string LastName {get;set;}

    public int Age {get;set;}

    public GenderEnum Gender {get;set;}

}

​

public enum GenderEnum

{

    Male,

    Female

}

​

​