C# 在JArray中使用LINQ
我有一个JSONC# 在JArray中使用LINQ,c#,json,linq,json.net,C#,Json,Linq,Json.net,我有一个JSON { "departments": [ { "2": {"city": "Petersburg", "employees": "1200"} }, { "1": {"city": "Ekaterinburg", "employees"
{
"departments": [
{
"2": {"city": "Petersburg", "employees": "1200"}
},
{
"1": {"city": "Ekaterinburg", "employees": "4000"}
}
]
}
如果我知道一个使用LINQ或其他东西的ID,如何获得城市的价值
我试过了
var id = 2;
json["departments"].Single(x=>x.Name==id.ToString())["city"];
但它不起作用,我得到一个编译错误:
“JToken”不包含“Name”的定义,并且找不到接受“JToken”类型的第一个参数的可访问扩展方法“Name”(是否缺少using指令或程序集引用?)
演示小提琴。您的LINQ查询可以按如下方式实现:
var id = "2";
var city = (string)json["departments"]
.Where(o => o[id] != null) // From the departments array, select the object where the required id property exists
.Select(o => o[id]["city"]).SingleOrDefault(); // An extract the value of "city" from the nested object.
或者,相当于:
var id = "2";
var city = (string)json["departments"]
.SelectMany(i => i) // Use SelectMany() to project the properties of the array items to a flat enumerable
.Cast<JProperty>() // Cast them to JProperty
.Where(p => p.Name == id) // Now you can use Name
.Select(p => p.Value["city"])
.SingleOrDefault();
SelectToken()
支持,而[*]
是JSONPath通配符运算符,指示应搜索所有数组项
演示小提琴
var id = "2";
var path = $"departments[*].{id}.city"; // departments[*].2.city
var city = (string)json.SelectToken(path);