KCC.cs

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

namespace NotifyExample

{
    class KCC
    {
        public event EventHandler<string> OnSettingChanged;

        private string setting;
        public string Setting
        {
            get { return setting; }
            set { OnSettingChanged?.Invoke(this, value); setting = value; }
        }

    }

    class Program
    {
        static void Main(string[] args)
        {
            var example = new KCC { Setting = "@yhaskell" };
            example.OnSettingChanged += (s, e) => Console.WriteLine($"Setting changed to \"{e}\" from \"{((KCC)s).Setting}\"");

            Console.WriteLine($"Name is {example.Setting}");
            example.Setting = "Yohann Haskell, Esq. (not really)";

            Console.WriteLine($"Name is now {example.Setting}");

        }
    }
}

NotifyExample.cs

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

namespace NotifyExample

{
    public class ChangeEventArgs<T> : EventArgs
    {
        public T Original { get; private set; }
        public T Value { get; private set; }

        public ChangeEventArgs(T from, T to)
        {
            this.Original = from;
            this.Value = to;
        }
    }

    class HasNotifiableProperties
    {
        public event EventHandler<ChangeEventArgs<string>> OnNameChanged;

        private string name;
        public string Name
        {
            get { return name; }
            set { OnNameChanged(this, new ChangeEventArgs<string>(name, value)); name = value; }
        }

    }

    class Program
    {
        static void Main(string[] args)
        {
            var example = new HasNotifiableProperties { Name = "@yhaskell" };
            example.OnNameChanged += (s, e) => Console.WriteLine($"Name changed to \"{e.Value}\" from \"{e.Original}\"");

            Console.WriteLine($"Name is {example.Name}");
            example.Name = "Yohann Haskell, Esq. (not really)";

            Console.WriteLine($"Name is now {example.Name}");


        }
    }
}