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C# Entity Framework Basics LINQ Queries Filtering a Query

Courses.Teacher

What am i doing wrong here.

Course has a Teacher navigation property, I am calling the Lastname property on that.

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())
            {
                return context.Courses
                    .Where(c => c.Teacher.LastName =="lastName")
                    .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

Steven Parker
Steven Parker
230,230 Points

Putting quotes around something creates a string literal. When referencing a variable, never put quotes around the variable name.

                    .Where(c => c.Teacher.LastName == lastName)

thanks, Stevan realized that later. Bad mistake.