c# - 如何从 session 对象中读取值

Question

在 Linq 中使用 sql server 存储过程，我将问题列表存储在 session 对象中，如下所示。

DataClassesDataContext myContext = new DataClassesDataContext();
var QuestionList = myContext.sp_GetAllQuestions().ToList();
Session["QuestionsList"] = QuestionList;

我如何从这个 session 对象中读取或转换值

var QuestionList= Session["QuestionsList"]

SQL存储过程是这样的

SELECT top 24 ROW_NUMBER() OVER (ORDER BY QuestionID) AS QuestionNo,Q.QuestionID,Q.Question,Q.Choices,Q.CorrectAnswer,
 Q.RelatedInfo,Q.QuestionType,CS.Section FROM Questions Q left join dbo.ChapterSection CS on Q.SectionID=CS.SectionID

Answer 1

我不喜欢每周类型 session ，因为每次使用都需要类型转换，所以我将所有类型/对象包装在一个强类型 session 包装器中。

包装基础:

public abstract class SessionBase<T> : SessionBase where T : new()
{
    private static readonly Object _padlock = new Object();

    private static string Key
    {
        get { return typeof(SessionBase<T>).FullName; }
    }

    public static T Current
    {
        get
        {
            var instance = HttpContext.Current.Session[Key] as T;

            if (instance == null)
            {
                lock (SessionBase<T>._padlock)
                {
                    if (instance == null)
                    {
                        HttpContext.Current.Session[Key] = instance = new T();
                    }
                }
            }

            return instance;
        }
    }

    public static void Clear()
    {
        var instance = HttpContext.Current.Session[Key] as T;
        if (instance != null)
        {
            lock (SessionBase<T>._padlock)
            {
                HttpContext.Current.Session[Key] = null;
            }
        }
    }

}

现在创建一个对象(将其标记为可序列化帮助)

[Serializable]
public QuestionCollection
{
  public QuestionCollection()
  {
    this.Questions = new List<Question>();
  }

  public List<Question> Questions { get; set; }
}

现在使 QuestionCollection 成为强类型的 QuestionCollectionSession

public QuestionCollectionSession : SessionBase<QuestionCollection>
{
}

现在你可以像这样使用它:

QuestionCollectionSession.Current.Questions.Add("Are you there?");

当你想从 session 中清除/删除它时:

QuestionCollectionSession.Clear();