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C# Entity Framework Basics LINQ Queries Filtering a Query

Im lost

In Repository.cs update the GetCoursesByTeacher method to return a list of the available courses whose teacher's last name equals the passed in lastName parameter value.

Instantiate an instance of the Context class within a using statement Return the results of calling Where and ToList on the context's Courses DbSet property

please help

Course.cs
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;

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

        public int Id { get; set; }
        public int TeacherId { get; set; }
        [Required, StringLength(200)]
        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; }
    }
}
Repository.cs
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;

namespace Treehouse.CodeChallenges
{
    public static class Repository
    {
        public static List<Course> GetCourses()
        {
            using (var context = new Context())
            {
                return context.Courses.ToList();
            }
        }

        public static List<Course> GetCoursesByTeacher(string lastName)
        {
            using (var context = new Context())
            {
                .Where cb => cb.Courses.ToList();
            }
    }
}
Teacher.cs
namespace Treehouse.CodeChallenges
{
    public class Teacher
    {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
    }
}

2 Answers

Karlijn Willems
Karlijn Willems
9,961 Points

In the course class, dubbelcheck the name of your Teacher property...

Repository.cs
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;

namespace Treehouse.CodeChallenges
{
    public static class Repository
    {
        public static List<Course> GetCourses()
        {
            using (var context = new Context())
            {
                return context.Courses.ToList();
            }
        }

        public static List<Course> GetCoursesByTeacher(string lastName)
        {
            using (var context = new Context())
            {
                return context.Courses.Include(cb => cb.Teacher).Where(cb => cb.Teacher.LastName == lastName).ToList();
            }
        }
    }
}