Add pizza classes

Add Pizza and PizzaService classes

Before you start to implement the form to manage pizzas, you need to have a data store that you can perform operations on.

• A model class is needed to represent a pizza in inventory.

• The model contains properties that represent the characteristics of a pizza.

• The model is used to pass data in the web app and to persist pizza options in the data store.

• In this unit, that data store will be a simple local in-memory caching service.

• In a real-world application, you would consider using a database, such as SQL Server, with Entity Framework Core.

Create a pizza model

1. Run the following command in your project's root directory to create a Models folder:

   mkdir Models

   Select the Models folder in the file explorer and add a new File called Pizza.cs.

   The project root now contains a Models directory with an empty Pizza.cs file. The directory name Models is a convention.

2. Add the following code to Models/Pizza.cs to define a pizza. Save your changes.

   using System.ComponentModel.DataAnnotations;
   
   namespace RazorPagesPizza.Models;
   
   public class Pizza
   {
       public int Id { get; set; }
   
       [Required]
       public string? Name { get; set; }
       public PizzaSize Size { get; set; }
       public bool IsGlutenFree { get; set; }
   
       [Range(0.01, 9999.99)]
       public decimal Price { get; set; }
   }
   
   public enum PizzaSize { Small, Medium, Large }

Add data service

1. Run the following command in your project's root directory to create a Services folder:

   mkdir Services

   Select the folder in the file explorer and add a new file called PizzaService.cs.

2. Add the following code to Services/PizzaService.cs to create an in-memory pizza data service. Save your changes.

   using RazorPagesPizza.Models;
   
   namespace RazorPagesPizza.Services;
   public static class PizzaService
   {
       static List<Pizza> Pizzas { get; }
       static int nextId = 3;
       static PizzaService()
       {
           Pizzas = new List<Pizza>
           {
               new Pizza { Id = 1, Name = "Classic Italian", Price=20.00M, Size=PizzaSize.    Large, IsGlutenFree = false },
               new Pizza { Id = 2, Name = "Veggie", Price=15.00M, Size=PizzaSize.Small,     IsGlutenFree = true }
           };
       }
   
       public static List<Pizza> GetAll() => Pizzas;
   
       public static Pizza? Get(int id) => Pizzas.FirstOrDefault(p => p.Id == id);
   
       public static void Add(Pizza pizza)
       {
           pizza.Id = nextId++;
           Pizzas.Add(pizza);
       }
   
       public static void Delete(int id)
       {
           var pizza = Get(id);
           if (pizza is null)
               return;
           Pizzas.Remove(pizza);
       }
   
       public static void Update(Pizza pizza)
       {
           var index = Pizzas.FindIndex(p => p.Id == pizza.Id);
           if (index == -1)
               return;
           Pizzas[index] = pizza;
       }
   }

   Note: This service provides a simple in-memory data caching service with two pizzas by default that your web app will use for demo purposes.

When you stop and start the web app, the in-memory data cache will be reset to the two default pizzas from the constructor of the PizzaService.