复杂的LINQ：嵌套，语句JSON.net和LINQ [英] Complex linq: Nested where statements JSON.net and linq

问题描述

我试图做到的是选择ttSheduleDay内dateTimeStart。 JSON的下方是一个员工的一个节点，该函数接收三个参数的empUID，日期和值（启动/停止或持续时间）。

What I'm trying to accomplish is to select the dateTimeStart inside the ttSheduleDay. The JSON beneath is a node of one employee, the function receives three parameters an empUID, a date and a value of (start / stop or duration).

我要选择的节点是其中dsShedule> ttEmployee> empUID等于第一个参数，其中ttShedule> ttSheduleDay> DAT等于日期参数和第三个参数，我会与if语句执行。下面的JSON

The node I want to select is where the dsShedule > ttEmployee > empUID equals the first parameter, where the ttShedule > ttSheduleDay > dat equals the date parameter and the third parameter I will execute with an if statement. Below the JSON

{
    "dsShedule": {
        "ttEmployee": [
            {
                "empUID": 2649,
                "empNameFirst": "firstname",
                "empNameLast": "lastname",
                "empFunction": "employee",
                "ttShedule": [
                    {
                        "UID": 47,
                        "empUID": 2649,
                        "datStart": "2013-05-20",
                        "datStop": "2013-05-20",
                        "regime": 1,
                        "state": "PLANNED",
                        "ttSheduleDay": [
                            {
                                "SheduleUID": 47,
                                "dat": "2013-05-20",
                                "dateTimeStart": "2013-05-20T08:00:00.000",
                                "dateTimeStop": "2013-05-20T17:00:00.000",
                                "duration": 8
                            }
                        ]
                    },
                    {
                        "UID": 57,
                        "empUID": 2649,
                        "datStart": "2013-05-21",
                        "datStop": "2013-05-21",
                        "regime": 1,
                        "state": "PLANNED",
                        "ttSheduleDay": [
                            {
                                "SheduleUID": 57,
                                "dat": "2013-05-21",
                                "dateTimeStart": "2013-05-21T08:00:00.000",
                                "dateTimeStop": "2013-05-21T17:00:00.000",
                                "duration": 8
                            }
                        ]
                    }
                ]
            },

在code我已经是选择ttShedule

The code I already have is to select the ttShedule

JObject jObj = JObject.Parse(json);
var linq = jObj["dsShedule"]["ttEmployee"]
                // first filter for a single emp by empUID
                         .First(emp => emp["empUID"].Value<int>() == Convert.ToInt16(empUID))
                         .SelectToken("ttShedule");

有人＃2所建议的code是：

The code suggested by someone on Stackoverflow was:

var linq = jObj["dsShedule"]["ttEmployee"]
         // first filter for a single emp by empUID
         .First(emp => emp["empUID"].Value<int>() == firstUID)
         // then select the ttShedule array of that emp
         .Select(emp => emp["ttShedule"])
         // now filter for whatever ttShedule you need
         .Where(shed => shed["ttSheduleDay"]
                      .Any(day => day["dat"].Value<DateTime>() 
                                             == new DateTime(2013, 5, 24))

但这个失败的ttShedule的select语句。我想知道我怎么可以扩大我的code选择与第二的dateTimeStart节点if语句。

But this failed on the select statement of ttShedule. I was wondering how i can expand my code to select the dateTimeStart node with the second if statement.

在此先感谢

推荐答案

这里有一种方法，你可以写你的查询：

Here's one way you could write your query:

var employeeId = 2649;
var date = new DateTime(2013, 5, 20);

var query =
    from emp in jObj.SelectToken("dsShedule.ttEmployee")
    where emp.Value<int>("empUID") == employeeId
    let day =
        (from sched in emp["ttShedule"]
        from d in sched["ttSheduleDay"]
        where d.Value<DateTime>("dat") == date
        select d).FirstOrDefault()
    where day != null
    select day.Value<DateTime>("dateTimeStart");

我怀疑你所面临的问题是，与指定的ID的雇员不存在与第一（）调用失败。这会不会遇到同样的问题。

I suspect the problem you were facing was that an employee with the specified id did not exist and the First() call failed. This will not run into the same problem.

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