Command Pattern

BuyCommand.cs

//Concrete Command class
public class BuyCommand : ICommand
{
    private Product Product;
    public string Name
    {
        get
        {
            return "Buy Command";
        }
    }
    public BuyCommand(Product product)
    {
        Product = product;
    }
    public void Execute()
    {
        Console.WriteLine("Executing {0}", Name);
        Product.Buy();
    }
}

ICommand.cs

//Command interface
public interface ICommand
{
    void Execute();
    string Name { get; }
}

Portal.cs

//Invoker class
public class Portal
{
    public string PortalName { get; set; }
    public Portal(string name)
    {
        PortalName = name;
    }
    public List<ICommand> orderList = new List<ICommand>();
    public void AddOrder(ICommand cmd)
    {
        orderList.Add(cmd);
    }
    public void ExecuteOrder()
    {
        Console.WriteLine("Executing all orders from {0}", PortalName);
        foreach(var order in orderList)
        {
            order.Execute();
        }
    }
}

Product.cs

//Receiver class
public class Product
{
    public int Quantity { get; set; }
    public string Name { get; set; }
    public Product(string prodName, int qty)
    {
        Name = prodName;
        Quantity = qty;
    }
    public void Buy()
    {
        Console.WriteLine("Purchased {0} quantities of {1}", Quantity, Name);
    }
    public void Sell()
    {
        Console.WriteLine("Sold {0} quantities of {1}", Quantity, Name);
    }
}

Program.cs

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

namespace CommandPattern
{
    //Client class
    class Program
    {
        static void Main(string[] args)
        {
            Product laptop = new Product("Laptop", 2);
            BuyCommand buyLaptop = new BuyCommand(laptop);
            SellCommand sellLaptop = new SellCommand(laptop);

            Portal portal = new Portal("Amazon.in");
            portal.AddOrder(buyLaptop);
            portal.AddOrder(sellLaptop);

            portal.ExecuteOrder();

            Console.ReadLine();
        }
    }
}

SellCommand.cs

//Concrete Command class
public class SellCommand : ICommand
{
    private Product Product;
    public string Name
    {
        get
        {
            return "Sell Command";
        }
    }
    public SellCommand(Product product)
    {
        Product = product;
    }
    public void Execute()
    {
        Console.WriteLine("Executing {0}", Name);
        Product.Sell();
    }
}

Command Pattern