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  • Entity Framework 出现 "此 ObjectContext 实例已释放,不可再用于需要连接的操作"

    错误的写法:

    public static List<Answer> GetAnswer_ByQuestionID(int questionID)
    {
      using (IA2SContext context = new IA2SContext())
    { var list = (from o in context.Answer where o.QuestionID == questionID select o).ToList(); return list; } }

    解决方案:(.ToList<Answer>())

    public static List<Answer> GetAnswer_ByQuestionID(int questionID)
    {
       using (IA2SContext context = new IA2SContext())
         {
              var list = (from o in context.Answer
                  where o.QuestionID == questionID
                  select o).ToList<Answer>();
              return list;
         }
    }

    第二种就是查询的时候包含另一张表:

    解决方案:(.Include("Answer"))

    public static List<Question> GetQuestionList_ByCategoryID(int categoryID)
    {
          using (IA2SContext context = new IA2SContext())
          {
               var list = (from o in context.Question.Include("Answer")
                   where o.CategoryID == categoryID && o.IsActive == true
                   select o).OrderBy(p => p.SortOrder).ToList<Question>();
               return list;
              }
         }
    }
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  • 原文地址:https://www.cnblogs.com/lizhao/p/2606888.html
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