如何使用LINQ獲得有序列表細節

Question

我有一個問卷類，它的細節，問題和問題組。該結構是這樣的：

創建詳細視圖，以顯示一Questionnaire和細節。細節應根據Sequence在QuestionGroup中顯示。使用LINQ，如何獲得一個調查問卷，其中的細節按問題組中的順序排列。

到目前爲止，當我創建一個LINQ語法得到解決這個問題：

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

我有2個問題：

1）我不能叫Include爲Question和QuestionGroup（立即加載）
.Include(q => q.QuestionnaireDetails.Question) < - 錯誤

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

2）I不能通過Sequence調用OrderBy，呼叫.FirstOrDefault()之前我加入
.OrderBy(q => q.QuestionnaireDetails.Question.QuestionGroup.Sequence) < - 錯誤

錯誤：
'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

我試圖從溶液@ JesseJames，稍作修改：

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 }; 

但我有錯誤：

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 }; 

編輯

您可能您正在使用實體框架喜歡這種語法

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 };