CODEWITHSUNDEEP
entity-frameworklazy-loadingentity-framework-4.1entity-relationship
yeomandev
yeomandev

Reputation: 11806

Why are my Entity Framework POCOs not loading the related entities correctly?

I have a code first model:

namespace InternetComicsDatabase.Models
{
    public class Issue
    {
        [Key]
        public int      IssueId     { get; set; }
        public int      Number      { get; set; }
        public string   Title       { get; set; }
        public DateTime Date        { get; set; }

        public virtual ICollection<Creator> Creators { get; set; }
    }

    public class Creator
    {
        [Key]
        public int      CreatorId   { get; set; }
        public string   FirstName   { get; set; }
        public string   MiddleName  { get; set; }
        public string   LastName    { get; set; }

        public virtual ICollection<Issue> Issues { get; set; }
    }

    public class Icbd : DbContext
    {
        public DbSet<Issue> Issues { get; set; }
        public DbSet<Creator> Creators { get; set; }
    }
}

In the controller, I am trying to load all the Creators that are associated with a particular issue:

    public string CreatorTest()
    {
        string output = "";
        var issue = db.Issues.Where(x => x.IssueId == 8);
        foreach (var item in issue.Creators)
            output += item.FirstName;
        return output;
    }

But this won't compile... Why won't this compile?

Specifically; the line that says:

        foreach (var item in issue.Creators)

won't compile because of an error that says:

Error   1   'System.Linq.IQueryable<InternetComicsDatabase.Models.Issue>' does not contain a definition for 'Creators' and no extension method 'Creators' accepting a first argument of type 'System.Linq.IQueryable<InternetComicsDatabase.Models.Issue>' could be found (are you missing a using directive or an assembly reference?) C:\Users\dropstuff\asp.net mvc\InternetComicsDatabase\InternetComicsDatabase\Controllers\HomeController.cs  19  31  InternetComicsDatabase

What's up with that? :-)

I went back and doublechecked my controller (you can just scroll up) and, yep; there it is! Creators is a property of Issues. So what gives? Maybe it has something to do with lazy loading?

Upvotes: 1

Views: 179

Answers (2)

William
William

Reputation: 8067

Try using Single() instead of Where() in db.Issues.Where(x => x.IssueId == 8)

var issue = db.Issues.Single(x => x.IssueId == 8);

Upvotes: 2

Craig Stuntz
Craig Stuntz

Reputation: 126577

Your query is wrong. You want:

var issue = db.Issues.Where(x => x.IssueId == 8).Single();

You are expecting a single issue, not a list of one issue.

Upvotes: 1

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