尝试从 Linq 查询 MVC "List doesn't contain definiton for ..." 错误填充 ViewModel 列表”

Question

我正在（尝试）构建一个多项选择测试应用程序，它将多项选择问题列表（select 列表）从控制器传递到视图。然后使用 foreach 循环填充视图，post 将答案返回给控制器，检查它们并增加每个正确答案的分数，然后更新数据库。

我正在尝试使用 Linq 查询填充视图模型列表（为了保持我的控制器精简，我通过服务层中的方法执行此操作）。

型号

Questions (db first)

namespace AccessEsol.Models
{
using System;
using System.Collections.Generic;

public partial class Question
{
    public Question()
    {
        this.ExamDets = new HashSet<ExamDet>();
    }

    public int QuID { get; set; }
    public string Text1 { get; set; }
    public string Text2 { get; set; }
    public string CorrectAnswer { get; set; }
    public string Foil1 { get; set; }
    public string Foil2 { get; set; }
    public string Foil3 { get; set; }
    public string Level_ { get; set; }
    public string GrammarPoint { get; set; }

    public virtual ICollection<ExamDet> ExamDets { get; set; }
}
}

考试

namespace AccessEsol.Models
{
using System;
using System.Collections.Generic;

public partial class Exam
{
    public Exam()
    {
        this.Candidates = new HashSet<Candidate>();
        this.ExamDets = new HashSet<ExamDet>();
    }

    public int ExamID { get; set; }
    public string Name { get; set; }
    public Nullable<System.DateTime> Date { get; set; }
    public int AdminID { get; set; }
    public string StartLevel { get; set; }

    public virtual Administrator Administrator { get; set; }
    public virtual ICollection<Candidate> Candidates { get; set; }
    public virtual ICollection<ExamDet> ExamDets { get; set; }
}
}

还有一个包含 CandID 的 Candidate 模型：

以及使用这些模型的视图模型：

namespace AccessEsol.Models
{
public class ExamQuestionsViewModel
{
    public int QuID { get; set; }
    public int CandID { get; set; }
    public int ExamId { get; set;  }
    public string Text1 { get; set; }
    public string Text2 { get; set; }
    public string CorrectAnswer { get; set; }
    public string Foil1 { get; set; }
    public string Foil2 { get; set; }
    public string Foil3 { get; set; }
    public string Level { get; set; }
    public string GrammarPoint { get; set; }

    public virtual ICollection<ExamDet> ExamDets { get; set; }

}
}

这是填充视图模型的方法：

        public static List<ExamQuestionsViewModel> AddQuestions()
    {

        AccessEsolDataEntities db = new AccessEsolDataEntities();

        string questionLevel = GetLevel(); 
        int currentCand = GetCandID();
        int currentExam = GetExamID(); 

        //model = new DataAccess().Populate();
        var qu = (from a in  db.Questions
                 where a.Level_ == questionLevel
                 select a).ToList(); 

    List<ExamQuestionsViewModel> exam = new List<ExamQuestionsViewModel>();


        foreach (var IDs in exam)
        {

            currentCand = exam.CandID;
            currentExam = exam.ExamId;

        }


      return (exam);
    }

我收到的错误消息是

'System.Collections.Generic.List<AccessEsol.Models.ExamQuestionsViewModel>'
does not contain a definition for 'ExamId' and no extension method 
'ExamId' accepting a first argument of type 
'System.Collections.Generic.List<AccessEsol.Models.ExamQuestionsViewModel>'      could be found (are you missing a using directive or an assembly
 reference?

我在这里做错了什么？非常感谢所有反馈。

Answer 1

请试试这个而不是你的 foreach:

foreach (var IDs in exam)
{    
    currentCand = IDs.CandID;
    currentExam = IDs.ExamId;    
}

尝试从 Linq 查询 MVC "List doesn't contain definiton for ..." 错误填充 ViewModel 列表”

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