3. Delegates and events, reference pitfall, C#

3. Delegates and events, reference pitfall

//3. Delegates and events, reference pitfall

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    public class Program
    {

delegate bool TestPointer(int a);   
        static event TestPointer SomeEvent; 
        
        public static void Main(string[] args)
        {
            var some = new SomeClass();

SomeEvent += some.SomeMethod;            
            SomeEvent(25);   
            
            //It's important to realize that at this point SomeEvent is holding a reference to SomeClass instance some.
            //(Since it needs one to invoke it's method when fired.)
            //It's important to release this reference when no longer needed, if SomeEvent is going to live in memory long time. 
            //Otherwise memory leaks may occur, since 'some' will live in memory just as long;
            
            SomeEvent -= some.SomeMethod; //Now 'some' can be garbage collected
            
            //SomeEvent(25); //SomeEvent == null since noone is subscribed
        }
    }
    
    public class SomeClass
    {
        byte[] HugeData;
        public bool SomeMethod(int a)
        {
            Console.WriteLine("From another class.");
            return true;
        }
    }
}


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