How to populate a view models using a linq query ASP.NET MVC 5 Entity Framework

Question

Ok so this is a follow-up from MVC 5 ASP.NET Entity Framework Collect Form Data through Range Input , My Database Structure Consists of a Survey Having Many Categories, A Ca

Answer 1

This might point you in the right direction, its using lambda expressions.

List<SurveyVM> surveys = DbContext.Survey.Select(s=> new SurveyVM {
    ID = s.ID,
    Name = s.Name,
    Categories = s.Category.Select(c => new CategoryVM {
        ID = c.ID,
        Name = c.Name,
        Questions = c.Question.Select(q=> new QuestionVM {
            ID = q.ID,
            Title = q.Title,
            Score = q.Score
        }).ToList()
    }).ToList()
}).SingleOrDefault();

This is off the top of my head as I dont have anything to test it with.

Also as a side note I would look at using EditorTemplates/DisplayTemplates instead of your loop in your view as it will make your code easier to read.

for (int i = 0; i < Model.Categories.Count; i++)
    {
        <div class="category">
            @Html.HiddenFor(m => m.Categories[i].ID)
            @Html.DisplayFor(m => m.Categories[i].Name)
            @for (int j = 0; j < Model.Categories[i].Questions.Count; j++)
            {
                <div class="question">
                    @Html.HiddenFor(m => m.Categories[i].Questions[j].ID)
                    @Html.DisplayFor(m => m.Categories[i].Questions[j].Title)
                    @Html.TextBoxFor(m => m.Categories[i].Questions[j].Score)
                    <div class="slider"></div>
                </div>
            }
            <div class="buttons">
                <button type="button" class="next">Next</button>
                <button type="button" class="previous">Previous</button>
            </div>
        </div>
    }

Answer 2

When you have Domain models and each of domain model have a lot of view models then it is the right time to use Automapper. All documentation you can find here:

https://github.com/AutoMapper/AutoMapper/wiki/Getting-started