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C# Entity Framework Basics LINQ Queries Filtering a Query

Posted by Travis Dalhoff
Travis Dalhoff
21,035 Points

Hi....I've been stuck on this for awhile. My code is not compiling. Any suggestions? Thanks!

Thanks for your 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())
            {                
                var Courses = context.Courses.Where(cb => cb.Teacher.lastName == lastName).ToList();
                return Courses;
            }
        }
    }
}
Teacher.cs 
namespace Treehouse.CodeChallenges
{
    public class Teacher
    {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
    }
}

1 Answer

James Churchill
STAFF
James Churchill
Treehouse Teacher
James Churchill
James Churchill
Treehouse Teacher

Travis,

When you're looking for help with a compiler error, it's helpful to include the error message that you're receiving.

Scanning your code, I noticed in the GetCoursesByTeacher method the following line of code:

var Courses = context.Courses.Where(cb => cb.Teacher.lastName == lastName).ToList();

Teacher.lastName doesn't reference a property on the Teacher class. The actual property name is LastName (starting with a capital "L"). I hope this helps.

Thanks ~James