Delegates

gistfile1.cs

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace LambdaExpressionTraining
{
    class MyButton
    {
        //public event EventHandler OnClickEvent = delegate { };
        private EventHandler _OnClickEvent;
        public event EventHandler OnClickEvent
        {
            add { _OnClickEvent += value; }
            remove { _OnClickEvent -= value; }
        }
        public EventHandler OnAnotherClickEvent = delegate { };

        private int myVar;
        public int MyProperty
        {
            get { return myVar; }
            set { myVar = value; }
        }

        public string MyProp { get; set; }
        public void Click()
        {
            //var handler = OnClickEvent;
            //if (handler != null)
            //{
            //OnClickEvent(null, EventArgs.Empty);
            OnAnotherClickEvent(null, EventArgs.Empty);
            //}
        }
    }

    class Program
    {
        delegate void DoSomething(string message);
        delegate string DoSomethingWithReturnResult(string message);
        delegate int PerformCalculation(int i1, int i2);

        static void Main(string[] args)
        {
            //DoImplementation("Good morning");
            //DoSomething ds = new DoSomething(DoImplementation);
            ////ds += new DoSomething(DoAnotherImplementation);
            //ds("called from delegate");

            //DoSomethingWithReturnResult ds = new DoSomethingWithReturnResult(DoImplementation);

            //ds -= new DoSomething(DoAnotherImplementation);

            //foreach (DoSomething inv in ds.GetInvocationList())
            //{
            //    Task.Factory.StartNew(() => 1);
            //}

            //ds("called after minus");


            //MyButton button = new MyButton();
            //button.OnClickEvent = Button_OnClickEvent;
            //button.OnAnotherClickEvent += Button_OnClickEvent1;

            //button.OnAnotherClickEvent = Button_OnClickEvent;
            //button.Click();


            //PerformCalculation calc = new PerformCalculation(Add);
            //PerformCalculation calc = new PerformCalculation(Minus);

            //Console.WriteLine(calc(1, 2)); 


            // .net 1.0
            DoSomething ds = new DoSomething(delegate (string msg)
            {
                Console.WriteLine("This is performed by anonymous method");
            });

            // .net 2.0
            DoSomething tempDelegate = delegate (string msg)
            {
                Console.WriteLine("anonymous method 2nd");
            };

            // .net 3.5
            DoSomething tempDelegate1 = (string msg) =>
            {
                Console.WriteLine("anonymous method 2nd");
            };

            DoSomething tempDelegate2 = (msg) =>
            {
                Console.WriteLine("anonymous method 2nd");
            };

            DoSomething tempDelegate3 = (msg) => Console.WriteLine("anonymous method 2nd");

            ds += tempDelegate;

            ds("called from delegate");

            //unregister
            ds -= tempDelegate;

            ds("called from delegate");

            //PerformCalculation calc = new PerformCalculation(delegate (int in1, int in2)
            //{
            //    return in2 * in1;
            //});



            //Console.WriteLine(calc(3,4));

            Console.WriteLine("Program is completed");
            Console.Read();


            //do long processing




            // GC = 3 -> 0,1,2

            // gen 0 = in few seconds
            // gen 1 = 10x more infrequent gen 0
            // gen 2 = 10x gen 1

            // finalizer queue
            // collection



        }

        static int Add(int i1, int i2)
        {
            return i1 + i2;
        }

        static int Minus(int i1, int i2)
        {
            return i1 - i2;
        }

        private static void Button_OnClickEvent1(object sender, EventArgs e)
        {
            Console.WriteLine("My button is clicked again");
        }

        private static void Button_OnClickEvent(object sender, EventArgs e)
        {
            Console.WriteLine("My button is clicked");
        }

        static void DoImplementation(string message)
        {
            Console.WriteLine("I'm doing something + {0}, Thread: {1}", message, Thread.CurrentThread.ManagedThreadId);
        }

        static void DoAnotherImplementation(string message)
        {
            Console.WriteLine("I'm doing something else + {0}, Thread: {1}", message, Thread.CurrentThread.ManagedThreadId);
        }
    }

    class UnmanagedObject : IDisposable
    {
        public void Dispose()
        {
            throw new NotImplementedException();
        }

        //destructor
        ~UnmanagedObject()
        {
            Dispose();
        }

        public UnmanagedObject()
        {

        }
    }
}