Memento Design pattern using C#

Memento pattern is not very popular design pattern but sometimes it perform heroic task to solve business problem. Sometime situation come like that- We can allow user to put his input and even after putting new input they want to revert back there previous value.

Say for example:- In online quiz user can give answer three time. At first user might give wrong answer ,then again wrong and in third time after giving answer before pressing confirm button she want to revert back the previous answer.

This kind of problem can able to solve by Memento design pattern.

So, What is the mechanism? How it’s happening ? very simple .

We will create a memento class which will be exact mirror of original class.  And when we will create object of original class that time same copy of that object we will create by memento class and will keep separately. Talking too much..Let’s look below code.

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Collections;

using System.Data.SqlClient;

using System.Data;

using System.Diagnostics;

namespace BlogProject

{

    //Momento Desing pattern

    class OriginalObject

    {

        public string Name { get; set; }

        public string Surname { get; set; }

        public Momento SetMomento { get; set; }

        public OriginalObject(string Name, String Surname)

        {

            this.Name = Name;

            this.Surname = Surname;

            this.SetMomento = new Momento(Name, Surname);

        }

        public void ChangeData()

        {

            this.Name = "New Name";

            this.Surname = "New Surname";

        }

        public void Revert()

        {

            Console.WriteLine(SetMomento.Name + SetMomento.Surname);

        }

    }

    class Momento

    {

        public string Name { get; set; }

        public string Surname { get; set; }

        public Momento(string Name, String Surname)

        {

            this.Name = Name;

            this.Surname = Surname;

        }

    }

    class Program

    {

        static void Main(string[] args)

        {

            OriginalObject obj = new OriginalObject("Sourav", "Kayal");

            obj.ChangeData();

            obj.Revert();

            Console.ReadLine();

        }

    }

}