WriteToConsole

using System;
using System.Collections.Generic;

namespace ExtensionMethods {
    public static class Extensions {

        /// <summary>
        /// Write all elements in the Enumeration to the Console
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="list"></param>
        public static void WriteToConsole<T>(this IEnumerable<T> list) {
            foreach (var obj in list) {
                Console.WriteLine(obj);
            }
        }

        /// <summary>
        /// Write all elements in the Enumeration to the Console
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="list">the enumeration written to the list</param>
        /// <param name="predicate">a transform function to apply to each element</param>
        public static void WriteToConsole<T>(this IEnumerable<T> list, Func<T, object> transfer) {
            foreach (var obj in list) {
                Console.WriteLine(transfer(obj));
            }
        }

    }
}

// Uses class Employee with Name and Salary
var l = new List<Employee>()
{
    new Employee("Fons", 2000),
    new Employee("Jim", 3000),
    new Employee("Ellen", 4000)
};

l.WriteToConsole();

l.WriteToConsole(emp => emp.Name);