EF Core Backing fields - expose property as another type?

Question

Assume I have an EF entity class Person, with a PhoneNumber on it. PhoneNumber is stored as a string type, but I want all accesses on the Person to go through Phone which h

Answer 1

The only way I've found that works in EF Core 2.0 is to create a public property with getters/setters with a name that does not match your backing field and mark it as NotMapped, like so:

    [NotMapped]
    [Display(Name = "Fire Type")]
    public Enums.FireType Type
    {
        get
        {
            Enums.FireType type;
            if (!Enum.TryParse(_fireType, out type))
                type = Enums.FireType.Fire; // default

            return type;
        }
        set
        {
            _fireType = value.ToString();
        }
    }
    
    private string _fireType;

Then in your DbContext's OnModelCreating method, tell it to create a column on the database table that acts like a backing property:

        // backing properties
        modelBuilder.Entity()
            .Property("FireType")
            .HasField("_fireType")
            .UsePropertyAccessMode(PropertyAccessMode.Field);

With that, I was finally able to create a successful migration that allowed me to have a private field on my model, a public transformative property on the model, and a single properly-named column in my database table. The only catch is that the public property and the private field can't share the same name (without sharing the same type), but that wasn't going to be the case for you, anyway.