Query a Model regarding its ICollection<> asp.net mvc - asp.net

Question

Using EntityFramework6 Code-First mvc 5 I have the following model:
Course
public class Course
{
public Course()
{
EnrolledStudentsEmails = new HashSet<ApplicationUser>();
}
[Key]
public string Id { get; set; }
public string UserName{ get; set; }
public string Name { get; set; }
public string Description { get; set; }
public ICollection<ApplicationUser> EnrolledStudentsEmails { get; set; }
I'm trying to query the following to IPagedList(Courses)
var model =
(from c in db.Courses
where searchTerm == null ||
c.Id.StartsWith(searchTerm) ||
c.Name.StartsWith(searchTerm)
select new
{
Id = c.Id,
Name = c.Name,
Description = c.Description,
UserName = c.UserName
}).AsEnumerable().Select(c => new Course
{
Id = c.Id,
Name = c.Name,
Description = c.Description,
UserName = c.UserName
}).ToPagedList(page, 10);
What should be the type of the ICollection EnrolledStudents if I want to use the AspNetUsers table generated when using user authentication?
The upper LINQ gets me All the courses in the database.
how can I get the courses that example#123.com is enrolled in?
Is it possible using my model? should I change my model?
Knowing that I can access the Email using:
User.Identity.Name

Answer 1

If your existing code works, your models are correct and you just want to filter by a known email, just use your collection:
var emailFilter = "example#123.com";
var model =
(from c in db.Courses
where (searchTerm == null ||
c.Id.StartsWith(searchTerm) ||
c.Name.StartsWith(searchTerm)) &&
c.EnrolledStudentsEmails.Any(e => e.Email == emailFilter)
select new
{
Id = c.Id,
Name = c.Name,
Description = c.Description,
UserName = c.UserName
}).AsEnumerable().Select(c => new Course
{
Id = c.Id,
Name = c.Name,
Description = c.Description,
UserName = c.UserName
}).ToPagedList(page, 10);