using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        var employees = new EmployeeRepo();

        var states = new StateRepo();

        SimpleJoin(employees.Get(), states.Get());

        Console.WriteLine("======================");

        OuterJoin(employees.Get(), states.Get());

    }

​

    public static void SimpleJoin(List<Employee> employees, List<State> states)

    {

        var employeeByState =

            from e in employees

            join s in states on e.StateId equals s.StateId

            where s.StateId == 2

            select new

            {

            e.LastName, s.StateName

            }

​

        ;

        foreach (var employee in employeeByState)

        {

            Console.WriteLine(employee.LastName + ", " + employee.StateName);

        }

    }

​

    public static void OuterJoin(List<Employee> employees, List<State> states)

    {

        var employeeByState =

            from e in employees

            join s in states on e.StateId equals s.StateId into employeeGroup

            from item in employeeGroup.DefaultIfEmpty(new State{StateId = 0, StateName = "NA"})select new

            {

            e.LastName, item.StateName

            }

​

        ;

        foreach (var employee in employeeByState)

        {

            Console.WriteLine(employee.LastName + ", " + employee.StateName);

        }

    }

}

​

public class StateRepo

{

    public List<State> Get()

    {

        return new List<State>()

        {new State()

        {StateId = 1, StateName = "PA"}, new State()

        {StateId = 2, StateName = "NJ"}};

    }

}

​

public class EmployeeRepo

{

    public List<Employee> Get()

    {

        return new List<Employee>()

        {new Employee()

        {FirstName = "John", LastName = "Smith", StateId = 1}, new Employee()

        {FirstName = "Jane", LastName = "Doe", StateId = 2}, new Employee()

        {FirstName = "Jack", LastName = "Jones", StateId = 1}, new Employee(){

            FirstName = "Pawan", LastName = "Shakya", StateId = 3

        }};

    }

}

​

public class State

{

    public int StateId

    {

        get;

        set;

    }

​

    public string StateName

    {

        get;

        set;

    }

}

​

public class Employee

{

    public string FirstName

    {

        get;

        set;

    }

​

    public string LastName

    {

        get;

        set;

    }

​

    public int StateId

    {

        get;

        set;

    }

}