CODEWITHSUNDEEP
c#asp.net-mvcentity-frameworklinqasp.net-mvc-4
Rob
Rob

Reputation: 199

How can I return single record of an IEnumerable object as part of my viewmodel?

I have a viewmodel:

public class CourseViewModel
{
    public int CourseID { get; set; }
    public string Title { get; set; }
    public string page_title { get; set; }
    public string titleabbrev { get; set; }
    public string Meta { get; set; }
    public string intro_1 { get; set; }
    public string intro_2 { get; set; }
    public string intro_3 { get; set; }
    public IEnumerable<course_section> Course_section { get; set; }
    public IEnumerable<course_subsection> Course_subsection { get; set; }
    public Enrollment Enrollments { get; set; }
}

In my controller I have the following:

var allcourse = db.Course_page
            .Where(i => i.titleabbrev == courseabbrev)
        .Include(i => i.course_sections.Select(c => c.course_subsections))
        .Include(i => i.enrollments);



        var viewModel = new CourseViewModel();

        viewModel.CourseID = allcourse.Single().CourseID;
        viewModel.page_title = allcourse.Single().page_title;
        viewModel.titleabbrev = allcourse.Single().titleabbrev;
        viewModel.Title = allcourse.Single().Title;
        viewModel.intro_1 = allcourse.Single().intro_1;
        viewModel.intro_2 = allcourse.Single().intro_2;
        viewModel.intro_3 = allcourse.Single().intro_3;

        viewModel.Course_section = allcourse
            .Single().course_sections
            .OrderBy(i => i.Order);


        viewModel.Course_subsection = viewModel.Course_section
            .SelectMany(c => c.course_subsections)
            .Where(i => i.Titleabbrev == sectionabbrev)
            .OrderBy(i => i.Order);


        return View(viewModel);

I want to send to the view viewmodel.enrollments, however I'm having problems with doing that as I only want to send a single enrollment record to the view in the viewmodel and within the course_page model enrollment is IEnumerable.

Presumably I should take only the single enrollment record when I am creating 'allcourse', however no matter what I try I don't seem to be able to do this and then return it to the view. I've tried for example:

var allcourse = db.Course_page
            .Where(i => i.titleabbrev == courseabbrev)
            .Where(b => b.enrollments.Single().UserID == User.Identity.GetUserId())
        .Include(i => i.course_sections.Select(c => c.course_subsections))
        .Include(i => i.enrollments);

What is the best way to send the viewmodel to the view with only the enrollment record that matches the currently logged in userID?

Edit - I've also tried things like:

var allcourse = db.Course_page
            .Where(i => i.titleabbrev == courseabbrev)
            Where(i => i.Enrollments.Any(b => b.UserID == User.Identity.GetUserId())
        .Include(i => i.course_sections.Select(c => c.course_subsections))
        .Include(i => i.enrollments);

Testing this in linqpad returned enrollment records where the UserID did not match.

Thanks

Upvotes: 0

Views: 1292

Answers (2)

Mohammad Akbari
Mohammad Akbari

Reputation: 4776

try this query :

var userId = User.Identity.GetUserId();

var viewModel = db.Course_page
    .Where(i => i.titleabbrev == courseabbrev)
    .Where(i => i.Enrollments.Any(b => b.UserID == userId))
    .Select(e => new CourseViewModel{
        CourseID = e.CourseID,
        page_title = e.page_title,
        titleabbrev = e.titleabbrev,
        Title = e.Title,
        intro_1 = e.intro_1,
        intro_2 = e.intro_2,
        intro_3 = e.intro_3, 
        Course_section = e.course_sections.OrderBy(i => i.Order)
            .ToList(),
        Course_subsection = e.course_sections
            .SelectMany(c => c.course_subsections)
                .Where(i => i.Titleabbrev == sectionabbrev)
                .OrderBy(i => i.Order).ToList()           
    }).Single();

Upvotes: 1

Jawad Umar
Jawad Umar

Reputation: 95

I would suggest you change your starting point to enrolments and then take values from course page and other linked entities..

e.g.

  var allcourse = db.Enrollments
        .Where(e => e.UserID == User.Identity.GetUserId())
        .Select(x => new CourseViewModel { 

    CourseID = e.Course_page.CourseID,
    ...
    ...

    Course_section = e.Course_page.course_sections.OrderBy(i => i.Order).FirstOrDefault
    ...
    ...
    ...
        });

Upvotes: 1

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