using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        List<Customer> cust1 = new List<Customer>()

        {

        new Customer()

        {

        FirstName = "Joe", LastName = "Smith", Age = 18

        }

​

        , new Customer()

        {

        FirstName = "Fasil", LastName = "Dires", Age = 31

        }

​

        , new Customer()

        {

        FirstName = "Bob", LastName = "Dires", Age = 31

        }

        }

​

        ;

        List<Customer> cust2 = new List<Customer>()

        {

        new Customer()

        {

        FirstName = "Kerem", LastName = "Erboke", Age = 45

        }

​

        , new Customer()

        {

        FirstName = "Fasil", LastName = "Dires", Age = 31

        }

        }

​

        ;

        var result = cust1.Join(cust2, c => c.LastName, t => t.LastName, (c, t) => c);

    }

}

​

class Customer

{

    public string FirstName

    {

        get;

        set;

    }

​

    public string LastName

    {

        get;

        set;

    }

​

    public short Age

    {

        get;

        set;

    }

} 

​

​