using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Program4();

    }

    private static void Program4()

        {

            Department Department1 = new Department() { DepartmentID = 1, DepartmentName = "HR" };

            Department Department2 = new Department() { DepartmentID = 2, DepartmentName = "Finance" };

​

            Employee Employee1 = new Employee() { EmployeeID = 1, DepartmentID = 1, EmployeeName = "Karan" };

            Employee Employee2 = new Employee() { EmployeeID = 2, DepartmentID = 2, EmployeeName = "Arjun" };

​

            Dictionary<Department, Employee> dict = new Dictionary<Department, Employee>()

            {

                { Department1, Employee1},

                { Department2, Employee2}

            };

​

            Department tempDepartment = default(Department);

            foreach (var item in dict)

            {

                if (item.Key.Equals(Employee1))

                {

                    tempDepartment = item.Key;

                    break;

                }

            }

            if (tempDepartment != default(Department))

                Console.WriteLine("Found EmployeeID {0} DepartmentID {1} (Name {2}).",

                                   Employee1.EmployeeID, tempDepartment.DepartmentID, Employee1.EmployeeName);

            else

                Console.WriteLine("Employee {0} not found.", Employee1.EmployeeName);

​

        }

}

​

public class Department : IEquatable<Employee>

    {

        public int DepartmentID { get; set; }

        public string DepartmentName { get; set; }

​

        public bool Equals(Employee employee)

        {

            if (employee == null)

                return false;

​

            if (this.DepartmentID == employee.DepartmentID)

                return true;

            else

                return false;

        }

​

        public override bool Equals(Object obj)

        {

            if (obj == null)

                return false;

​

            Employee employeeObj = obj as Employee;

            if (employeeObj == null)

                return false;

            else

                return Equals(employeeObj);

        }

        public override int GetHashCode()

        {

            return this.DepartmentID.GetHashCode();

        }

    }

​

    public class Employee

    {

        public int EmployeeID { get; set; }

        public int DepartmentID { get; set; }

        public string EmployeeName { get; set; }

    }