EF Meny-To-Meny relation Circular loading

Question

Hi, 

Lets say I have EntityA that have  multiple of EntityB and EntityB can have multiple of EntityA. For simplicity:

class Student
{
   public string Name {get;set;}
   public virtual ICollection<Teacher> Teachers{get;set;}
}

class Teacher
{
   public string Name {get;set;}
   public virtual ICollection<Student> Students{get;set;}
}

I do mapping like this:

HasMany(x => x.Teachers)
   .WithMany(x => x.Students)
   .Map(x => 
      {
         x.MapLeftKey("StudentId");
         x.MapRightKey("TeacherId");
         x.ToTable("StudentTeacher");
       });

Lazy loading is turned of. 

Then I want to load Student including Teachers (meaning only Name of Teacher) but not other Students and then Teachers curculary. I tried this.

var student = _context.Students.Where(x => x.Name == studentName)
     .Include(x=>x.Teachers)
     .SingleOrDefault();

But I really get a objects. I only want to load the first level.

How can I do this?

            

Answer 1

Hi Novak Savic,

>>But I really get a objects. I only want to load the first level. How can I do this?

According to your description, it seems that we could return a custom result like this:

using (var db = new EFDemoContext())
            {
                string studentName = "Cole";
                var student = db.Students.Where(x => x.Name == studentName)
                 .Select(s => new
                 {
                     StudentId = s.StudentId,
                     Name = s.Name,
                     Teachers = s.Teachers.Select(t=>t.Name)
                 }).SingleOrDefault();

                foreach (var item in student.Teachers)
                {
                    Console.Write("{0}", item);
                }

Best regards,

Cole Wu

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