CODEWITHSUNDEEP
entity-frameworkasp.net-mvc-4
davecove
davecove

Reputation: 1071

MVC4 Model : Using a List<> as a Property

I have a Model with a class like this

public class Feature
{
    public int ID { get; set; }
    public string Desc { get; set; }
}

and one like this:

public class Camera
{
    public int ID { get; set; }
    public string ModelName { get; set; }
    public List<Feature> Features { get; set; }
}

in the Seed() method I do something like this:

context.Features.AddOrUpdate
    (
            f => f.Desc,
            new Feature { Desc = "PTZ" },
            new Feature { Desc = "AutoFocus" },
            new Feature { Desc = "AutoIris" },
            new Feature { Desc = "PoE" }
    );

context.Cameras.AddOrUpdate
    (
        c => c.Name,
        new Camera
        {
            ModelName = "P3301",
            Features = new System.Collections.Generic.List<Feature>()
            {
                context.Features.Where(f => f.Desc.Contains("PTZ")).First()
            }
        }
    );
context.Cameras.AddOrUpdate
    (
        c => c.Name,
        new Camera
        {
            ModelName = "P3301p",
            Features = new System.Collections.Generic.List<Feature>()
            {
                context.Features.Where(f => f.Desc.Contains("PoE")).First(),
                context.Features.Where(f => f.Desc.Contains("PTZ")).First()
            }
        }
    );

After running update-database I see the records in the Features and Cameras tables, but the Features table has a new Camera_ID field that contains a single Camera ID. I was expecting a Feature_Camera table or something so that a feature could be crossed up with many different cams.

What am I missing here? How do I say that a camera can have a a collection of non-unique features?

Upvotes: 1

Views: 145

Answers (1)

Slauma
Slauma

Reputation: 177153

If you want a many-to-many relationship between Camera and Feature either add a collection to Feature...

public List<Camera> Cameras { get; set; }

...or define the relationship with Fluent API:

modelBuilder.Entity<Camera>()
    .HasMany(c => c.Features)
    .WithMany()
    .Map(m =>
    {
        m.ToTable("CameraFeatures");  // name of the link table
        m.MapLeftKey("CameraID");
        m.MapRightKey("FeatureID");
    });

If you don't do one of these changes EF will assume that the relationship is one-to-many resulting in a foreign key to Camera in the Features table.

Upvotes: 1

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