不相等的列表<>在实体框架中 [英] Not equal list<> in entity framework

问题描述

我有4张桌子如下



表1位置A

I have 4 tables as following

table 1 Location A

public class CustmLocationA {
        public int Location1_ID { get; set; }
        public string Location1 { get; set; }
        public string Location1_Descrip { get; set; }
        public bool IsActive { get; set; }
}

表2位置B

Table 2 location B

public class CustmLocationB{
       pubblic int Location2_ID { get; set; }
       public string Location2 { get; set; }
       public string Location2_Descrip { get; set; }
       public int Location1_ID { get; set; }
       public bool IsActive { get; set; }
}

表3位置C

Table 3 Location C

public class CustmLocationC {

        public int Location3_ID { get; set; }
        public string Location3 { get; set; }
        public string Location3_Descrip { get; set; }
        public int Location2_ID { get; set; }
        public bool IsActive { get; set; }
        //Location B data
        public string Location2 { get; set; }
        [NotMapped] 
        public bool LocBIsActive { get; set; }
        //location A data
        [NotMapped] 
        public int Location1_ID { get; set; }
        [NotMapped] 
        public string Location1 { get; set; }
        [NotMapped] 
        public bool LocAIsActive { get; set; }
        [NotMapped] 
        public string LocAandB { get; set; }

}

表4

Table 4

public class CustmContact
    {
        
        public int contactID { get; set; }
        public int Location3_ID { get; set; }
        public int UserID { get; set; }
        public bool Notify { get; set; }
        public bool Access { get; set; }
        [NotMapped]
        public string UserName { get; set; }
        [NotMapped]
        public string LocationAll { get; set; }

    }

我的尝试：



我正在尝试选择所有位置C以及位置A和B中的相关表格信息之后我需要在表格中选择所选用户位置联系人（第4张表格）之后我需要从所选位置删除所有选定的用户表但我发现无法应用于int类型的操作数和< int>列表在这一行（a.Location3_ID！=（来自db.contacts中的z，其中z.UserID == UserID选择z.Location3_ID））





//按用户ID获取未选择的位置

What I have tried:

I'm trying to select all location C with related tables information in location A and B after that I need to select the selected user locations in table Contact (4th table) after that I need to remove all selected user table from selected locations but I found that cannot be applied to operands of type int and list of <int> in this line (a.Location3_ID != (from z in db.contacts where z.UserID == UserID select z.Location3_ID))


//Get Un-selected location by user ID

public List GetSelectedLocByUID (int UserID = 0)
        {
var data = (from LocC in db.locationsC
           join LocB in db.locationsB on LocC.Location2_ID equals LocB.Location2_ID
           join LocA in db.locationsA on LocB.Location1_ID equals LocA.Location1_ID
           select new CustmLocationC
                        {
                            Location1_ID = LocA.Location1_ID,
                            Location1 = LocA.Location1,
                            LocAIsActive = LocA.IsActive,
                            Location2_ID = LocB.Location2_ID,
                            Location2 = LocB.Location2,
                            LocBIsActive = LocB.IsActive,
                            Location3_ID = LocC.Location3_ID,
                            Location3 = LocC.Location3,
                            Location3_Descrip = LocC.Location3_Descrip,
                            LocAandB = LocA.Location1 + "-" + LocB.Location2,
                            IsActive = LocC.IsActive
 }).Where(a => a.LocAIsActive == true && a.LocBIsActive == true && a.IsActive == true 
                        
&& a.Location3_ID != (from z in db.contacts where z.UserID == UserID select z.Location3_ID)

).OrderBy(a => a.Location1).ToList();

            return (data);
            }

推荐答案

当前逻辑a.Location3_ID！=（来自db.contacts中的z，其中z.UserID = = UserID select z.Location3_ID）正在尝试将一个位置与一个或多个位置进行比较。哪个不行，就像说一个苹果等于1个或更多苹果。



根据发布的内容，我建议

The current logic "a.Location3_ID != (from z in db.contacts where z.UserID == UserID select z.Location3_ID)" is trying to compare ONE location with ONE or MANY location. Which will not work, like saying if 1 apple equals to 1 or more apple.

Based on what posted here, I would suggest

//store the list of Location3_ID for a user in a list
List<int> loc3s = (from z in db.contacts
                               where z.UserID == UserID 
                               select z.Location3_ID).ToList();
//then replace a.Location3_ID != (from z in db.contacts where z.UserID == UserID select z.Location3_ID) with below
//return all the result where Location3_ID not belong to the user
!loc3s.Contains(a.Location3_ID )

这篇关于不相等的列表&lt;&gt;在实体框架中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！