CODEWITHSUNDEEP
c#asp.netentity-frameworkentity
Craig
Craig

Reputation: 18734

ASP.Net Entity Framework and Foreign Keys

I am battling to work out how to handle foriegn keys with Entity Framework, when editing or adding a new record. For example, I have a person table, which has a timezone_id linking to my timezone table.

But the model seems to not include timezone_id. I see it's a new way of doing things, but ... how do I store my record?

My method:

 public static string CreateUser(string username, string email, string password, string firstname, string surname, int timezoneId)
    {
        user u = new user();
        u.surname = surname;
        u.firstname = firstname;
        u.email = email;
        u.password = password;
        u.username = username;
        Db.AddTousers(u);

        Db.SaveChanges();

        return username;

    }

I can't do u.timezone_id = timezoneid;

I only have u.timezone (which seems to be the actual entity), and u.timezoneReference, which I am not sure what to do with.

Upvotes: 2

Views: 1248

Answers (3)

Avinash
Avinash

Reputation: 11

If you are using EF v1, and you dont want to add the object as it is, you would need to do this.

u.TimezoneReference.EntityKey = new EntityKey("DB.TimeZone", "ID", id)

id is the foreign key.

If you are using EF v4 and still not getting the forgeign keys exposed then I guess you did not check the option to generate foreign keys while creating the model.

Upvotes: 1

Rup
Rup

Reputation: 34418

I think you have to fill in the timezone entity from the database, i.e.

u.timezone = DB.TimezoneSet.FirstOrDefault(tz => tz.Id == timezoneid);

assuming you've generated the set name with EF3; it'll be DB.Timezones by default in EF4. If this is EF4 then you can also regenerate your EDMX for that table with ID columns included too - there's an option on the front page of the wizard.

The TimezoneReference property is used to test whether child entities have been loaded, force them to load, etc.

Upvotes: 1

Henk Holterman
Henk Holterman

Reputation: 273784

I only have u.timezone

Yes, the model should expose a FK as a Navigation property. Just assign your TimeZone object there.

Upvotes: 1

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