EF projections many to many not loading - entity-framework

Question

I have four classes defined as follows:
public class Operator : Base
{
public string Name { get; set; }
public string URL { get; set; }
public ICollection<Address> Addresses { get; set; }
public ICollection<Contact> Contacts { get; set; }
public ICollection<Application.Application> Applications { get; set; }
}
public class Address : Base
{
public String Street{ get; set; }
public int? ParentId { get; set; }
public Operator Parent { get; set; }
public ICollection<Application.Application> Applications { get; set; }
}
public class Contact : Base
{
public string Name { get; set; }
public int? ParentId { get; set; }
public Operator Parent { get; set; }
public ICollection<Application.Application> Applications { get; set; }
}
public class Application : Base
{
[MaxLength(300)]
public String Name { get; set; }
public ICollection<Operator.Operator> Operators { get; set; }
public ICollection<Operator.Address> Addresses { get; set; }
public ICollection<Operator.Contact> Contacts { get; set; }
}
public class Base
{
public int Id { get; set; }
//public int BaseObjectId { get; set; }
TimeZoneInfo _easternZone = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");
private DateTime _modifiedDate;
public DateTime ModifiedDate
{
get { return this._modifiedDate; }
set
{
this._modifiedDate = DateTime.SpecifyKind(value, DateTimeKind.Unspecified);
this._modifiedDate = TimeZoneInfo.ConvertTimeFromUtc(this._modifiedDate, _easternZone);
}
}
private DateTime _createdDate;
[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
public DateTime CreatedDate
{
get { return this._createdDate; }
set
{
this._createdDate = DateTime.SpecifyKind(value, DateTimeKind.Unspecified);
this._createdDate = TimeZoneInfo.ConvertTimeFromUtc(this._createdDate, _easternZone);
}
}
public bool Disabled { get; set; }
}
public class DB : DbContext
{
public DbSet<EF.Complaint.Complaint> Complaints { get; set; }
public DbSet<EF.Category.Category> Categories { get; set; }
public DbSet<EF.Action.Action> Actions { get; set; }
public DbSet<EF.Medium.Medium> Mediums { get; set; }
public DbSet<EF.Priority.Priority> Priorities { get; set; }
public DbSet<EF.Complaint.Comment> Comments { get; set; }
public DB()
{
this.Database.Log = s => { System.Diagnostics.Debug.WriteLine(s); };
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Properties<DateTime>().Configure(c => c.HasColumnType("datetime2"));
modelBuilder.Configurations.Add(new ComplaintConfig());
modelBuilder.Configurations.Add(new CategoryConfig());
modelBuilder.Configurations.Add(new ActionConfig());
modelBuilder.Configurations.Add(new MediumConfig());
modelBuilder.Configurations.Add(new PriorityConfig());
modelBuilder.Configurations.Add(new CommentConfig());
base.OnModelCreating(modelBuilder);
}
}
Operator, Contact and Address can all belong to a particular application. So you could have a structure like this:
Operator 1 - belongs to App1 and App2
Child contact 1 - belongs to App1
Child Contact 2 - belongs to App2
Child Address 1 - belongs to App2
I am trying to build a method that returns a list of Operators for a particular Application and includes Addresses and Contacts of that operator that also belong to that Application
Here is a query I have concocted so far
public IEnumerable<Operator> GetForApp(string name)
{
return (Context.Operators.Where(x => x.Applications.Any(y => y.Name == name))
.Select(x => new
{
x,
Addresses = x.Addresses.Where(y => y.Applications.Any(z => z.Name == name)),
Contacts = x.Contacts.Where(y => y.Applications.Any(z => z.Name == name)),
Applications = x.Applications
}).AsEnumerable()
.Select(n => n.x));
}
This works in a sense that the basic members of Operator get loaded as well as Addresses and Contacts get loaded and filtered correctly...What doesn't get loaded is Applications and I can't figure out why. They only difference I see is that Addresses/Contacts and Operator is many-to-one and Applications and Operator is many-to-many.

Answer 1

You must use lazy loading feature or include your related object directly in your query.
public class Operator : Base
{
public string Name { get; set; }
public string URL { get; set; }
public ICollection<Address> Addresses { get; set; }
public ICollection<Contact> Contacts { get; set; }
// by adding virtual keyword EF could generate proxy classes and
// fetch actual objects when are needed.
public virtual ICollection<Application.Application> Applications { get; set; }
}
Or in your query directly include Application:
public IEnumerable<Operator> GetForApp(string name)
{
return (Context.Operators.Where(x => x.Applications.Any(y => y.Name == name))
.Include(x=>x.Applications)
.Select(x => new
{
x,
Addresses = x.Addresses.Where(y => y.Applications.Any(z => z.Name == name)),
Contacts = x.Contacts.Where(y => y.Applications.Any(z => z.Name == name)),
Applications = x.Applications
}).AsEnumerable()
.Select(n => n.x));
}