Question

我正在尝试过滤并获取一个列表，如果我的主要对象使用Linq和我的嵌套列表。我需要的是 - List<Category>

class Category contains List<Order> and List<Price>

但我得到的结果是由两个子对象分组，因此我得不到确切的结果。我想分组这个以获得结果。以下是我的Linq查询，

我在这里做错了什么？

var resultList = (
    from category in Connection.Table<Category>().ToList()
    join order in Connection.Table<Order>().ToList()
        on category.Id equals order.CategoryId
    join price in Connection.Table<Price>().ToList()
        on category.Id equals price.CategoryId
    where category.Id == TestID
    select new {
        category.ID,
        category.Name,
        order,
        price
    } into grou
    group grou by new {
        grou.Id
    } into grp
    select new Category {
        Id = grp.Id,
        Order = grp.Select(x => x.order).ToList(),
        Price = grp.Select(x => x.price).ToList()
    }).ToList();

Answer 1

尝试以下内容。至少有一个案例你有ID而不是Id：

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {

         }
    }
    public class cConnection
    {
        public cConnection Connection { get; set; }

        public List<cTable<Entity>> Table<Entiry>() { return null; } 

        public void Test()
        {
            int TestID = 123;

            var resultList = (from mainObjectEntity in Connection.Table<MainObjectEntity>().ToList()
                    join child1Entity in Connection.Table<Child1Entity>().ToList()
                    on mainObjectEntity.Id equals child1Entity.MainObjectEntityId
                    join child2Entity in Connection.Table<Child2Entity>().ToList()
                    on mainObjectEntity.Id equals child2Entity.MainObjectEntityId
                    where mainObjectEntity.TestId == TestID
                    select new
                    {
                        id = mainObjectEntity.TestId,
                        mainObjectEntity = mainObjectEntity,
                        child1 = child1Entity,
                        child2 = child2Entity
                    })
                    .GroupBy(x => x.id)
                    .Select(grp => new {
                        TestID = grp.FirstOrDefault().id,
                        Child1Entity = grp.Select(x => x.child1).ToList(),
                        Child2Entity = grp.Select(x => x.child2).ToList()
                     }).ToList();
        }
    }
    public class cTable<T> : Entity
    {
        public int MainObjectEntityId { get; set; }
        public int TestId { get; set; }
    }
    public class Entity
    {
        public int Id { get; set; }
    }
    public class Child1Entity : Entity
    {

    }
    public class Child2Entity : Entity
    {
    }
    public class MainObjectEntity : Entity
    {
    }


}

LINQ with group by用于嵌套列表

1 个答案: