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C# Entity Framework Basics LINQ Queries Filtering a Query

Posted by Marcus Stigall
Marcus Stigall
13,252 Points

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
Karlijn Willems
Karlijn Willems
9,961 Points

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

Tanmoy Chowdhury
Tanmoy Chowdhury
12,622 Points
Tanmoy Chowdhury
Tanmoy Chowdhury
12,622 Points
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();
            }
        }
    }
}