Изменение цены продуктов - паттерн Компоновщик

using System.Collections.Generic;
 
namespace Composite
{
    public abstract class Component
    {
        public List<Component> components = new List<Component>();
 
        public Component(List<Component> components) => this.components = components;
 
        public Component()
        {
        }
 
        public virtual uint GetPrice()
        {
            uint price = 0;
            foreach (var component in components)
                price += component.GetPrice();
            return price;
        }
 
        public virtual void Add(Component component) => components.Add(component);
 
        public virtual void Remove(Component component) => components.Remove(component);
 
        public virtual void Clear() => components.Clear();
    }
}

using System;
 
namespace Composite
{
    public abstract class Product : Component
    {
        private uint price;
 
        public Product(uint price = 0) => this.price = price;
 
        public override uint GetPrice() => price;
 
        public uint SetPrice(uint price)
        {
            if (price < 0)
                throw new ArgumentOutOfRangeException();
            return this.price = price;
        }
 
        public override void Add(Component component) => throw new NotSupportedException();
 
        public override void Clear() => throw new NotSupportedException();
 
        public override void Remove(Component component) => throw new NotSupportedException();
    }
}

    interface IComponent
    {
        decimal Price { get; }//only getter !
    }
 
    class Product : IComponent
    {
        public decimal Price { get; set; }//getter and setter
    }
 
    class Box : IComponent
    {
        private readonly List<IComponent> children = new List<IComponent>();
 
        public decimal Price => children.Sum(c=>c.Price);//only getter
 
        public void Add(IComponent c) => children.Add(c);
        public void Remove(IComponent c) => children.Remove(c);
    }