C# + EntityFramework:通过查询将多个组转换为嵌套 JSON
Posted
技术标签:
【中文标题】C# + EntityFramework:通过查询将多个组转换为嵌套 JSON【英文标题】:C# + EntityFramework: Convert multiple group by query to nested JSON 【发布时间】:2015-09-12 14:51:40 【问题描述】:我做了以下 linq 声明
C#
var list = from row in repository.GetAllEntities()
group row by new row.RegionString, row.SubRegionString, row.CountryString into g
select new g.Key.RegionString, g.Key.SubRegionString, g.Key.CountryString, Count = g.Count() ;
return Json(list, JsonRequestBehavior.AllowGet);
返回
[
"RegionString":"Americas",
"SubRegionString":"",
"CountryString":"",
"Count":2
,
"RegionString":"Americas",
"SubRegionString":"NorthAmerica",
"CountryString":"Canada",
"Count":5
,
"RegionString":"Americas",
"SubRegionString":"NorthAmerica",
"CountryString":"US",
"Count":3
,
"RegionString":"Americas",
"SubRegionString":"SouthAmerica",
"CountryString":"Chile",
"Count":3
,
"RegionString":"EMEA",
"SubRegionString":"AsiaPacific",
"CountryString":"Australia",
"Count":2
,
"RegionString":"EMEA",
"SubRegionString":"AsiaPacific",
"CountryString":"Japan",
"Count":1
,
"RegionString":"EMEA",
"SubRegionString":"SouthernEurope",
"CountryString":"Turkey",
"Count":1
,
"RegionString":"EMEA",
"SubRegionString":"WesternEurope",
"CountryString":"",
"Count":1
]
但我正在尝试将其变成这种格式
[
name: "Americas",
children: [
name: "NorthAmerica",
children: [ "name": "Canada", "count": 5 ,
"name": "US", "count": 3 ]
,
name: "SouthAmerica",
children: [ "name": "Chile", "count": 1 ]
,
],
,
name: "EMA",
children: [
name: "AsiaPacific",
children: [ "name": "Australia", "count": 2 ,
"name": "Japan", "count": 1 ]
,
name: "SouthernEurope",
children: [ "name": "Turkey", "count": 1 ]
,
],
]
如何修改语句以获得我正在寻找的结果?非 linq 答案也是可以接受的。
编辑: Region 是 SubRegion 的父级,SubRegion 是 Country 的父级,Count 是属于 Country 的唯一项目数
【问题讨论】:
你能解释一下除了格式之外你想做什么吗? IE。子区域是区域字符串的子区域 刚刚用层次结构编辑了答案。希望这会有所帮助 你可以用我现在正在尝试解决的字典字典来做到这一点 【参考方案1】:这是您想要的 linq 查询(为了便于阅读,我删除了 -String
后缀):
var list =
from entity in repository.GetAllEntities()
group entity by entity.Region into regions
let childrenOfRegions =
from region in regions
group region by region.SubRegion into subregions
let countriesOfSubRegions =
from subregion in subregions
group subregion by subregion.Country into countries
select new Name = countries.Key
select new Name = subregions.Key, Children = countriesOfSubRegions
select new Name = regions.Key, Children = childrenOfRegions ;
这个查询中没有Count
,因为我不太明白你在数什么。
我在这里所做的是将行分组到区域中,在最后一行中,您可以看到 select new Name = regions.Key, ...
我返回区域的部分。
要获得孩子,您需要将区域分组为子区域(与区域相同)。你一直重复这个到国家,你就完成了。
【讨论】:
以上是关于C# + EntityFramework:通过查询将多个组转换为嵌套 JSON的主要内容,如果未能解决你的问题,请参考以下文章
C# EntityFramework Code First 迁移