Enums with EF code-first - standard method to seeding DB and then using?

问题

Is there a standard way to using Enums in EF code-first? There seems to be some examples making use of a wrapper class for the enum.

However, I would like to be able to define the enum and have the enum values also seeded into the database using the database initializer. There doesn't seem to be much point in defining the enum and creating a wrapper, if I then have to seed the database table manually from the enum.

回答1:

Now supported : http://blogs.msdn.com/b/adonet/archive/2011/06/30/announcing-the-microsoft-entity-framework-june-2011-ctp.aspx

The Microsoft Entity Framework June 2011 CTP introduces both new runtime and design-time features. Here are some of the new runtime features:

The Enum data-type is now available in the Entity Framework. You can use either the Entity Designer within Visual Studio to model entities that have Enum properties, or use the Code First workflow to define entities that have Enum objects as properties. You can use your Enum property just like any other scalar property, such as in LINQ queries and updates...

There are several new features for the Entity Framework Designer within Visual Studio:

The Entity Designer now supports creation of Enums, spatial data-types and table-value functions from the designer surface...

回答2:

Unfortunately, enums are not natively supported on EF 4.1. Here's one rather known article on how to deal with them: Faking enums on EF 4. It does, however, require a wrapper.

There's a simpler way to map enums in EF 4 however: just create an int property on your class to represent the int value of the enum. That's the property that EF should map, then have a "mini wrapper" property to allow you to use the enum.

public class Appointment 
{   
    public int ID { get; set; }
    public string Description { get; set; }

    // This property will be mapped
    public int DayOfWeekValue { get; set; }

    public DayOfWeek Day
    {
        get { return (DayOfWeek) DayOfWeekValue; }
        set { DayOfWeekValue = (int) value; }
    }
}

public enum DayOfWeek
{
    Monday,
    Tuesday,
    Wednesday,
    Thursday,
    Friday,
    Saturday,
    Sunday
}

On generating the database, EF will happily ignore any type it doesn't know how to map, but the int property will be mapped.

Note: This is taken directly from my answer to another enum and EF question: EF 4.1 Code First - map enum wrapper as complex type

回答3:

I Wrote a post about that. You can use Code First Migrations to add your enum values to the database. Look here: http://linqto.net/blog/2012/10/entity-framework-code-first-and-enum-support/

来源：https://stackoverflow.com/questions/6344032/enums-with-ef-code-first-standard-method-to-seeding-db-and-then-using

标签

entity-framework-4.1

ef-code-first