CODEWITHSUNDEEP
c#asp.net-mvc
mishi
mishi

Reputation: 43

Property list in a Model property couldn't be mapped while trying to migrate

I'm setting up a migration in an MVC5 that has a Model that's called "Order" with 3 properties, one of them is a class of PizzaModel. PizzaModel has the code below, what I'm trying to do is to enable multiple instances of pizzas in a single Order, so one Order can have many pizzas.

public class PizzaModel
{
    [Key]
    public int Id { get; set; }
    public List<PizzaSet> Pizzas { get; set; }
    public int Cost { get; set; }


}
public class PizzaSet
{
    public enum Toppings { GreenOlives, BulgarianCheese, Onions, Mushrooms, Peppers, Basil, Sausage, Pepperoni, Ham, Beef }
    public enum Sauces { BBQ, Islands }
    public enum Size { Personal, Medium, Family }

    public Size PizzaSize { get; set; }
    public List<Sauces> PizzaSauces { get; set; }
    public List<Toppings> PizzaToppings { get; set; }
}

Is this a wrong approach for a migration?

Upvotes: 2

Views: 260

Answers (2)

Stefan
Stefan

Reputation: 17658

You have enums as your list type.

If youre storing this data in a database. The database needs a placeholder to store the enum values.

In general this is done by a table.

So, if you make classes of your enums, these will be translated to tables and the mapping will work.

public class Topping 
{
     public string Name {get;set;}
}

Use this class as your list type.

Do note that you need to fill the topping, sauces and etc. tables. The good news is: you can extend them without changing the code :-)

Alternatively, you can put the

[NotMapped]

attribute on your property. Do note that this won't help you in your specific case because it would not store the toppings in the database then.

Upvotes: 1

Aleks
Aleks

Reputation: 1689

Your PizzaSet class is using a List of Enums, which will not map to a database schema in EF.

If you want to use an enum for Sauces and Toppings and want to allow multiple selections, you need to use the [Flags] property for the enum, to treat it as a bit field.

public class PizzaSet
{
    [Flags]
    public enum Toppings { GreenOlives = 1, BulgarianCheese = 2, Onions = 4, Mushrooms = 8, Peppers = 16, Basil = 32, Sausage = 64, Pepperoni = 128, Ham = 256, Beef = 512 }

    [Flags]
    public enum Sauces { BBQ = 1, Islands = 2 }

    public enum Size { Personal, Medium, Family }

    public Size PizzaSize { get; set; }
    public Sauces PizzaSauces { get; set; }
    public Toppings PizzaToppings { get; set; }
}

Then Toppings and Sauces become a bit field of possible values (notice the values will need to represent unique bits)

To select multiple toppings:-

PizzaSet ps = new PizzaSet();

ps.Toppings = Toppings.GreenOlives | Toppings.Peppers;

However, given your list of toppings and sauces may change over time, it's probably better to have a separate table that lists toppings, and use a join table (since it's EF Core)

Upvotes: 2

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