无法在MVC 4中获得特定类别的子类别，并且无法设计类别和子类别模型类的问题 [英] not able to get subcategory of particular category in mvc 4 and designing issue of category and subcategory model class

问题描述

我正在开发MVC中的帮助台系统.

i am working on help desk system in mvc.

我只有一个用于用户和技术人员的主表.

i have only one master table for user and technicians.

这是我的类别课程:

 public class Category
    {
        [Key]
        public int CategoryId { get; set; }
        public string Name { get; set; }


        public virtual ICollection<SubCategory> subCategory { get; set; }//category can have more than 1 category
    }

这是我的子类别:

public class SubCategory
    {
          [Key]
          public int SubcategoryId { get; set; }
          public string Name { get; set; }
          public int CategoryId { get; set; }
          public virtual ICollection<TicketInfo> ticketsInfo { get; set; }/to keep track of all tickets under this particular subcategory.
          public virtual ICollection<UserDetails> technicianInfo { get; set; }//to keep track of technician and user under this subcategory.

          public virtual Category category { get; set; }
    }

这是我的usermaster(定义了用户和技术人员)

This is my usermaster(it defines both user and technician)

public class UserDetails
    {
        public string UserName { get; set; }
        [Key]
        public int UserId { get; set; }
        public string FName { get; set; }
        public string LName { get; set; }
        public string PhoneNo { get; set; }
        public string EmailId { get; set; }
        [DataType(DataType.Password)]
        public string Password { get; set; }

        public int SubcategoryId { get; set; }
        public int AddressId { get; set; }
        public Boolean IsActive { get; set; }
        public DateTime CreatedDate { get; set; }

        public virtual ICollection<Role> Roles { get; set; }

        public virtual SubCategory subCategory { get; set; }

    }

现在当我触发dis查询时::

now when i am firing dis query::

public list<Category> FetchTicketDetailsforSubcategory(int categoryId)
        {
            using (HelpDeskdbContext context = new HelpDeskdbContext())
            {
                var category = from temp in context.Category where                temp.CategoryId == categoryId select temp;

                return category;
            }   
        }

它只是显示类别，而不显示该类别下的子类别.

it just show me the category but not subcategory under that category.

在子类别上向我显示此信息: ObjectContext实例已被处置，不能再用于需要连接的操作.

it show me this on subcategory:The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.

任何人都可以找出我的班级设计出了什么问题吗?

can any one figure out what is wrong with my class design??

推荐答案

尝试一下

context.Category.Where(x=>x.CategoryId == categoryId).SelectMany(x=>x.subCategory).ToList()

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