如何使用LINQ获取有序列表的详细信息

Question

I have questionnaire class with its detail, question, and question group. The structure is like this:

I create the details view to display a Questionnaire and the details. The details should be displayed based on Sequence in QuestionGroup . Using LINQ, how to get a questionnaire with its details ordered by sequence in question group.

So far, when I create a LINQ syntax to get solve this:

var questionnaire = db.Questionnaires
   .Include(q => q.QuestionnaireDetails)
   .FirstOrDefault(q => q.QuestionnaireID == questionnaireID);

I've got 2 problems:

1) I cannot call Include for Question and QuestionGroup (eager loading)
.Include(q => q.QuestionnaireDetails.Question) <-- error

Error:
Cannot convert lambda expression to type 'string' because it is not a delegate type

2) I cannot call OrderBy by Sequence , before call .FirstOrDefault() I added
.OrderBy(q => q.QuestionnaireDetails.Question.QuestionGroup.Sequence) <-- error

Error:
'System.Collections.Generic.ICollection<MvcApplication1.Models.QuestionnaireDetail>' does not contain a definition for 'Question' and no extension method 'Question' accepting a first argument of type 'System.Collections.Generic.ICollection<MvcApplication1.Models.QuestionnaireDetail>' could be found (are you missing a using directive or an assembly reference?)

UPDATE

I tried solution from @JesseJames, with a little modification:

var questionnaire = from qg in db.QuestionGroups
                    join q in db.Questions on qg.QuestionGroupID equals q.QuestionGroupID
                    join qd in db.QuestionnaireDetails on q.QuestionID equals qd.QuestionID
                    join qe in db.Questionnaires on qd.QuestionnaireID equals qe.QuestionnaireID
                    orderby qg.Sequence
                    select new Questionnaire { 
                        QuestionnaireID = qe.QuestionnaireID, 
                        Date = qe.Date,
                        Respondent = qe.Respondent,
                        QuestionnaireDetails = qe.QuestionnaireDetails };

but I've got error:

The entity or complex type 'MvcApplication1Model.Questionnaire' cannot be constructed in a LINQ to Entities query.

Answer 1

var query = from qg in db.QuestionGroup
            from q in db.Questions.Where(r=>r.QuestionGroupId == qg.QuestionGroupId)
            from qd in db.QuestionnaireDetail.WHere(r=>r.QuestionId== q.QuestionId)
            from qe in db.Questionnaire.Where(r=>r.QuestinnareId == qd.QuestinnareId)
            orderby qg.Sequence
            select new { Questionnaire = q, QuestionnaireDetail = qd };

EDIT

You may prefer this syntax

var query = from qg in db.QuestionGroup
            join q in db.Questions on qg.QuestionGroupId equals q.QuestionGroupId
            join qd in db.QuestionnaireDetail on q.QuestionId equals qg.QuestionId
            join qe in db.Questionnaire on qd.QuestinnareId equals qe.QuestinnareId
            orderby qg.Sequence
            select new { Questionnaire = q, QuestionnaireDetail = qd };