c# - 返工 linq 查询以返回嵌套对象

Question

我有一个像这样的数据库表

我的查询 linq 看起来像

   var selectedNotifications = _dbContext.UserNotificationTypeDeliveryChoice
    .Include(m => m.NotificationGroup)
    .Include(m => m.DeliveryType)
    .Where(m => m.UserDefId == userDefId && m.UserTypeId == (int)userType)
    .Select(m => new NotificationGroup()
    {
      NotificationGroupId = m.NotificationGroup.NotificationGroupId,
      Name = m.NotificationGroup.Name,
      DefaultDeliveryType = m.DeliveryType,
      HasChoosen = true
    }).ToList();

在我的模型中，我使用虚拟道具来填写外键属性 DeliveryType。它看起来像这样（JSON）：

[
  {
    "notificationGroupId": 1,
    "name": "Comments",
    "defaultDeliveryType": {
      "deliveryTypeId": 2,
      "name": "Email"
    },
    "hasChoosen": true
  },
  {
    "notificationGroupId": 2,
    "name": "Q&A",
    "defaultDeliveryType": {
      "deliveryTypeId": 2,
      "name": "Email"
    },
    "hasChoosen": true
  },
  {
    "notificationGroupId": 3,
    "name": "Services",
    "defaultDeliveryType": {
      "deliveryTypeId": 2,
      "name": "Email"
    },
    "hasChoosen": true
  },
  {
    "notificationGroupId": 4,
    "name": "Trial",
    "defaultDeliveryType": {
      "deliveryTypeId": 2,
      "name": "Email"
    },
    "hasChoosen": true
  },
  {
    "notificationGroupId": 4,
    "name": "Trial",
    "defaultDeliveryType": {
      "deliveryTypeId": 1,
      "name": "SMS"
    },
    "hasChoosen": true
  }
]

但是，我有同一个 NotificationGroupId 的多条记录，我希望列出如下：

[
  {
    "notificationGroupId": 4,
    "name": "Trial",
    "defaultDeliveryType": {
      "deliveryTypeId": 1,
      "name": "SMS"
    },
    "defaultDeliveryType": {
        "deliveryTypeId": 2,
        "name": "Email"
      },
    "hasChoosen": true
  }
]

请注意“notificationGroupId”的区别： 4，它需要有嵌套的传递类型。

更新 #1 我设法实现了一些目标，但我仍然需要使用 Select 投影仪语句映射到我的模型。

这是一个例子：

var selectedNotifications = _dbContext.UserNotificationTypeDeliveryChoice
                            .Include(m => m.NotificationGroup)
                            .Include(m => m.DeliveryType)
                            .Where(m => m.UserDefId == userDefId && m.UserTypeId == (int)userType)
                            .GroupBy(p => p.NotificationGroupId,
                                     p => p.DeliveryType,
                                     (key, g) => new { NotificationGroupId = key, DeliveryTypes = g });

更新 #2强文本

    public class UserNotificationTypeDeliveryChoice
    {
        public List<NotificationGroup> NotificationGroups { get; set; }
        //public List<DeliveryType> DeliveryTypes { get; set; }
        public long UserNotificationTypeDeliveryChoiceId { get; set; }
        public int? UserDefId { get; set; }
        public int? UserCompanyOrInstitutionId { get; set; }
        public byte NotificationGroupId { get; set; }
        public byte DeliveryTypeId { get; set; }
        public int UserTypeId { get; set; }
        public virtual DeliveryType DeliveryType { get; set; }
        public virtual NotificationGroup NotificationGroup { get; set; }
        public virtual UserDef UserDef { get; set; }
    }

NotificationGroup 和 DeliveryType 的模型：

    public class NotificationGroup
    {
        public NotificationGroup()
        {
            UserNotificationTypeDeliveryChoice = new HashSet<UserNotificationTypeDeliveryChoice>();
            NotificationGroupUserType = new HashSet<NotificationGroupUserType>();
        }
        //public List<DeliveryType> DeliveryTypes { get; set; }
        public byte NotificationGroupId { get; set; }
        public string Name { get; set; }
        public string Description { get; set; }
        //public bool HasChoosen { get; set; }
        public virtual DeliveryType DefaultDeliveryType { get; set; }
        public byte DefaultDeliveryTypeId { get; set; }
        public virtual ICollection<UserNotificationTypeDeliveryChoice> UserNotificationTypeDeliveryChoice { get; set; }
        public virtual ICollection<NotificationGroupUserType> NotificationGroupUserType { get; set; }
    }

    public class DeliveryType
    {
        public DeliveryType()
        {
            NotificationGroup = new HashSet<NotificationGroup>();
            UserNotificationTypeDeliveryChoice = new HashSet<UserNotificationTypeDeliveryChoice>();
            NotificationGroupUserType = new HashSet<NotificationGroupUserType>();
        }

        public byte DeliveryTypeId { get; set; }
        public string Name { get; set; }
        public string Description { get; set; }

        public virtual ICollection<NotificationGroup> NotificationGroup { get; set; }
        public virtual ICollection<UserNotificationTypeDeliveryChoice> UserNotificationTypeDeliveryChoice { get; set; }
        public virtual ICollection<NotificationGroupUserType> NotificationGroupUserType { get; set; }
    }
}

这是我通过 EF Core 映射的模型描述：

标签： c#asp.net-mvclinqasp.net-core

Answer 1

如果你有一个非唯一的 ID，你不能按 NotificationGroup 分组，你必须坚持使用 ID。

要保留 NotifigrationGroup 的名称，您必须将 NotificationGroup 保留为 GroupBy 的 TElement。（这就是为什么 p=>p。）

稍后在结果选择器中，您可以从其中一个元素中选择一个名称，只需选择第一个 NotificationGroup 的名称。如果您愿意，您可以在此处选择 DeliveryTypes。

var selectedNotifications = _dbContext.UserNotificationTypeDeliveryChoice
                            .Include(m => m.NotificationGroup)
                            .Include(m => m.DeliveryType)
                            .Where(m => m.UserDefId == userDefId && m.UserTypeId == (int)userType)
                            .GroupBy( p => p.NotificationGroupId, p => p, 
                    (key,g) => new { 
                         NotificationId = key, 
                         Name = g.First().Name, 
                         DeliveryTypes = g.Select(x => x.DeliveryTypes)
                               }););