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I have two tables with the id columns joined in a third table. In my controller, I am returning a single item from 1 table and need to list items from a second table that relates to the single item from the first table. Here is my current broken code:

Depots Model:

    public class Depot
{
    public int DepotID { get; set; }
    public string Name { get; set; }

    public virtual ICollection<VendorDepot> VendorDepots { get; set; }
}

Vendors Model:

     public class Vendor
{
    public int VendorID { get; set; }
    public string CompanyName { get; set; }

    public virtual ICollection<VendorDepot> VendorDepots { get; set; }
}

VendorDepots Model(join table):

     public class VendorDepot
{
    public int VendorDepotID { get; set; }
    public int DepotID { get; set; }
    public int VendorID { get; set; }

    public virtual Depot Depot { get; set; }
    public virtual Vendor Vendor { get; set; }
}

Context file:

     public class GuideContext : DbContext
{
    public GuideContext(DbContextOptions<GuideContext> options)
        : base(options)
        { }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<VendorDepot>()
           .HasKey(t => new { t.VendorID, t.DepotID });

        modelBuilder.Entity<VendorDepot>()
            .HasOne(pt => pt.Vendor)
            .WithMany(p => p.VendorDepots)
            .HasForeignKey(pt => pt.VendorID);

        modelBuilder.Entity<VendorDepot>()
            .HasOne(pt => pt.Depot)
            .WithMany(t => t.VendorDepots)
            .HasForeignKey(pt => pt.DepotID);
    }

    public virtual DbSet<Depot> Depots { get; set; }
    public virtual DbSet<VendorDepot> VendorDepots { get; set; }
    public virtual DbSet<Vendor> Vendors { get; set; }
}

Here is my controller info:

      public IActionResult Index(int id)
    {
        var thisDepot = _context.Depots.FirstOrDefault(d => d.DepotID == id);

        thisDepot.Vendors = _context.Vendors.Join(_context.VendorDepots.Where(d => d.DepotID == id).ToList(),
           d => d.VendorID,
           d => d.VendorID,
           (o, i) => o).ToList();

        return View(thisDepot);
    }

So the problem I am having is that I can view the specific depot that I select on a new view page but I cannot view the vendors that are associated with the specific depot. I had the code at one point to where I could view all the venders but they weren't specific to the specific depot. Another attempt left me with only viewing vendors that had an id identical to itself, ie.. 1 and 1 or 5 and 5.

Thanks.

Just made some updates, found a misspelling and added some new code for my context and controller files. I really could use some help on the controller!

cbkinor
  • 1
  • 2

1 Answers1

0

May need to eager load your data. Something like (haven't tried it myself)

var thisDepot = _context.Depots .Single(d => d.DepotID == id).Include(x => x.VendorDepots).Include(y => y.Vendor);

Might be tricky with the many to many relationship. Here is a decent article on Lazy/Eager/Explicit loading examples:

http://www.asp.net/mvc/overview/getting-started/getting-started-with-ef-using-mvc/reading-related-data-with-the-entity-framework-in-an-asp-net-mvc-application

sjkype
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  • Hey sjkype, thanks for the input and the link. I must have read that page a dozen times and tried using the loading examples. Not sure how to list all vendors associated with specific depots. Am I overthinking this? I just cannot find any specific docs on many-to-many relationships that can give me ideas. – cbkinor Jul 31 '16 at 19:42
  • I have made a few more updates to my code. Still could use some help finishing the controller file. I feel I'm getting close but still missing some stuff. – cbkinor Aug 04 '16 at 17:03
  • Finally figured it out with some help from an old classmate Nicholas Jensen-Hay. Thanks for the Help Nick! – cbkinor Aug 05 '16 at 12:43