Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

C# Entity Framework Basics Extending Our Entity Data Model Defining a Many-to-Many Relationship with an Explicit Bridge Entity

Posted by Alexander Olson
Alexander Olson
13,067 Points

Defining a Many to-Many Relationship with an Explicit Bridge Entity Task 3 of 3

Need help finding my error

Course.cs 
using System.Collections.Generic;

namespace Treehouse.CodeChallenges
{
    public class Course
    {
        public Course()
        {
            Students = new List<CourseStudent>();
        }

        public int Id { get; set; }
        public int TeacherId { get; set; }
        public string Title { get; set; }
        public string Description { get; set; }
        public int Length { get; set; }

        public Teacher Teacher { get; set; }
        public ICollection<CourseStudent> Students { get; set; }
    }
}
CourseStudent.cs 
using System.Collections.Generic;

namespace Treehouse.CodeChallenges
{
    public class CourseStudent
    {
        public int Id { get; set; }
        public int CourseId { get; set; }
        public int StudentId { get; set; }
        public decimal Grade { get; set; }

        public Course Course { get; set; }
        public Student Student { get; set; }
    }
}
Student.cs 
using System.Collections.Generic;

namespace Treehouse.CodeChallenges
{
    public class Student
    {
        public Student()
        {
             CourseStudent Students = new List<CourseStudent>();
        }

        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }

        public ICollection<Student> Students { get; set; }
    }
}

2 Answers

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

Task 3 is much like task 2.

Remember in task 2 you had to change both the collection type and the initialization? For task 3 you do essentially the same thing in a different file.

But it doesn't look like you've changed the collection type yet.

Alexander Olson
Alexander Olson
13,067 Points
Alexander Olson
Alexander Olson
13,067 Points

Figured it out. Thank you Steven!