集团通过对象的嵌套列表

Question

嗨，大家好，我有这样一个类：

public class supervisorAnswerQuesttionPres 
    { 
     public string date { set; get; } 
     public List<string> questionList { set; get; } 
     public List<string> answerList { set; get; } 
    } 

我有一个返回这个类的列表

 List<PresentClass.supervisorAnswerQuesttionPres> temp 
      = dbconnect.tblAnswerLists 
         .Where(i => i.StudentNum == studentNumber && i.username==objstu.Return_SupervisorUserName_By_StudentNumber(studentNumber)) 
         .ToList() // <-- This will bring the data into memory. 
         .Select(i => new PresentClass.supervisorAnswerQuesttionPres 
          { 
           answerList = Return_Answer_List(studentNumber,i.dateOfAnswer.Value.Date), 
           questionList = Return_Question_List(studentNumber, i.dateOfAnswer.Value.Date), 
           date = ConvertToPersianToShow(i.dateOfAnswer.Value.Date) 
          }) 
         .OrderByDescending(i => i.date) 
         .ToList(); 

所以我需要一个查询将我的列表分组临时通过日期并再次选择所有3列我的意思是日期，问题列表，答案列表。

我只是想执行这个查询 我使用LINQ asp.net视觉2012

Answer 1

var temp 
     = dbconnect.tblAnswerLists 
        .Where(i => i.StudentNum == studentNumber && i.username==objstu.Return_SupervisorUserName_By_StudentNumber(studentNumber)) 
        .ToList() // <-- This will bring the data into memory. 
        .Select(i => new PresentClass.supervisorAnswerQuesttionPres 
         { 
          answerList = Return_Answer_List(studentNumber,i.dateOfAnswer.Value.Date), 
          questionList = Return_Question_List(studentNumber, i.dateOfAnswer.Value.Date), 
          date = ConvertToPersianToShow(i.dateOfAnswer.Value.Date) 
         }) 
        .GroupBy(i => i.date) 
        .OrderByDescending(i => i.Key) 
        .ToList(); 

temp实际上是List<IGrouping<string, PresentClass.supervisorAnswerQuesttionPres>>类型后，我的分组结果。