PhiHuyHoang

private delegate string MyDelegate(string s1, string s2);

PhiHuyHoang

public string WhatUp(string firstName, string lastName)
        {
            return $"What's up {firstName} {lastName}";
        }

PhiHuyHoang

        Action<string> logMethods;

        public void AddLogMethod(Action<string> newLogMethod)
        {
            logMethods += newLogMethod;
        }

        public void LogThis(string msg)
        {
            logMethods?.Invoke($"[{DateTime.Now.ToLongDateString()}] {msg}");

PhiHuyHoang

        static void ConsoleLog(string s)
        {
            Console.WriteLine($"[CONSOLE] {s}");
        }
        static void Main(string[] args)
        {
            /// section 1 ///
            Logger log = new Logger();
            log.AddLogMethod(ConsoleLog);
            log.AddLogMethod(delegate (string s) { Console.WriteLine($"[ANON] {s}"); });

PhiHuyHoang

log.LogThis("Hello, delegates"); Thread.Sleep(1000);
log.LogThis("Apache started..."); Thread.Sleep(1000);
log.LogThis("Mysql started..."); Thread.Sleep(1000);
log.LogThis("Exim started..."); Thread.Sleep(1000);
log.LogThis("Pureftpd started..."); Thread.Sleep(1000);
log.LogThis("Influxdb started..."); Thread.Sleep(1000);
log.LogThis("Google started..."); Thread.Sleep(1000);
log.LogThis("Git started..."); Thread.Sleep(1000);
log.LogThis("Docker started..."); Thread.Sleep(1000);
log.LogThis("Apache stopped..."); Thread.Sleep(1000);

PhiHuyHoang

List<string> filtered = log.Filter(entry => entry.ToLower().Contains("apache")); // Actually this is LinQ, very cool. I'll talk about this later.
foreach(string s in filtered)
{
    Console.WriteLine(s);
}

PhiHuyHoang

        List<string> entries;

        public Logger()
        {
            entries = new List<string>();
            AddLogMethod(msg => entries.Add(msg)); //or we can use: AddLogMethod(entries.Add);
        }

        //Example for Func

PhiHuyHoang

public static class [YOUR_CLASS_NAME]
{
    public static [RETURN_TYPE] [METHOD_NAME](this [TYPE_NAME] s)
    {
       // TODO: Write code here
    }
}
/*
---[YOUR_CLASS_NAME]---: What ever you like
---[RETURN_TYPE]---: What ever you want

PhiHuyHoang

    public static class HoangExtension
    {
        public static void PlusWithHoang(this string s)
        {
            Console.WriteLine($"{s} - Make from HoangExtension");
        }
    }
   
    class Program
    {

PhiHuyHoang

class Post
{
public string status { get; set; }
public DateTime timestamp { get; set; }
}