CODEWITHSUNDEEP
c#entity-framework
Jedi_Maseter_Sam
Jedi_Maseter_Sam

Reputation: 813

Retrieve Values From List In Entity Framework

There are two different models in my project: Movie and Actor. Movie has a list of actors and Actor has a list of movies. What I want to do is given a movie, get all of the actors, and then for each actor examine their movies acted in.

So, to get the information, I use:

var movie = context.Movies.Include("Cast.ActingCredits").FirstOrDefault(m => m.Key == key);

The problem is that while the list ActingCredits is not null, there are no values in it. Is there something that I am missing to load the values in the list? ActingCredits is an ICollection<Movie>.

 public class Actor : ModelBase
 {
     public ICollection<Movie> ActingCredits { get; set; }
 }

public class Movie : ModelBase
{
    public string Title { get; set; }
    public DateTime Year { get; set; }
    public Genre Genre { get; set; }
    public int RunTime { get; set; }
    public int Sales { get; set; }
    public ICollection<Actor> Cast { get; set; }
}

EDIT: It has come to my attention that this may be wrong and is the cause of the issue.

protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Movie>().HasMany(p => p.Cast).WithMany();
        modelBuilder.Entity<Actor>().HasMany(m => m.ActingCredits).WithMany();
    }

Upvotes: 0

Views: 179

Answers (3)

Jedi_Maseter_Sam
Jedi_Maseter_Sam

Reputation: 813

The problem was with the database and how I initialized it.

protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Movie>().HasMany(p => p.Cast).WithMany(p => p.ActingCredits);
        modelBuilder.Entity<Actor>().HasMany(m => m.ActingCredits).WithMany(m => m.Cast);

    }

Thanks to all who commented. I believe I understand entity framework a whole lot more now.

Upvotes: 1

David
David

Reputation: 1871

I suggest adding this:

using System.Data.Entity;

And then you can do the Include with strongly typed variables

var movie = context.Movies.Include(r => r.Cast)

However what I think you really want is to use Select instead of Include?

var movie = context.Movies.Select(r => r.Cast).SelectMany(r => r.ActingCredits);

Upvotes: 0

Alin
Alin

Reputation: 394

You are not typing the correct name of the property in the include. Try this:

    var movie = context.Movies.Include("Cast").FirstOrDefault(m => m.Key == key);

Also, make sure that your database is populated before executing this. I tested this and it works, it retrieves everything.

Upvotes: 1

Related Questions