1

我有这个xml

<?xml version="1.0" encoding="utf-8" ?>
<Departments>
 <Department>
  <id>001</id>
  <Section>
    <SectionId>001001</SectionId>
    <Room>
      <RoomID>001001001</RoomID>
      <Owner>guest1</Owner>
    </Room>
    <Room>
      <RoomID>001001002</RoomID>
      <Owner>guest11</Owner>
    </Room>
  </Section>
  <Section>
    <SectionId>001002</SectionId>
    <Room>
      <RoomID>001002001</RoomID>
      <Owner>guest2</Owner>
    </Room>
 </Section>
</Department>
</Departments>

这是我使用 Linq to Xml 的代码

var xDoc = XDocument.Load(inputUrl);

var sections = from el in xDoc.Descendants("Department")
                       where el.Element("id").Value.Equals("001")
                       select el.Element("Section");

var rooms = from el in sections
               where el.Element("SectionId").Value.Equals("001001")
               select el.Element("Room");

var roomsList = (from el in rooms
            select new Room
            {
                roomID = (string)el.Element("RoomID"),
                owner = (string)el.Element("Owner")
            }).ToList();

我的问题是我在列表中只得到了 1 个房间，但我应该得到两个。如果这是使用 LINQ to xml 的正确方法，请提出建议，我对 LINQ 相当陌生。

4

5 回答 5

2

作为其他答案的替代方法，您可以使用Extensions.XPathSelectElements Method (XNode, String)（确保将using System.Xml.XPath指令添加到文件顶部）：

string 
    departmentId = "001", 
    sectionId = "001001";
var xDoc = XDocument.Load(inputUrl);
var rooms = xDoc.XPathSelectElements(
    String.Format(
        "//Department[id={0}]/Section[SectionId={1}]/Room",
        departmentId,
        sectionId))
    .Select(el => new Room
    {
        roomID = (string)el.Element("RoomID"),
        owner = (string)el.Element("Owner")
    }).ToList();

这是个人喜好的问题。我发现这写起来更短，更容易阅读。

于 2013-08-16T09:32:29.413 回答
2

更改sections和rooms查询：

var sections = xDoc.Descendants("Department")
                   .FirstOrDefault(x => (string)x.Element("id") == "001")
                   .Elements("Section");

var rooms = sections.Where(x => (string)x.Element("SectionId") == "001001")
                    .Elements("Room");

有了这些，您将获得 2 个房间。

为什么你的代码不起作用？

  1. select el.Element("Section")只选择其中section的第一个元素Department- 你永远无法从中获得section空间id == "001002"
  2. select el.Element("Room")inrooms查询仅返回每个匹配部分的第一个房间。

您可以更改Element并Elements添加其他SelectMany(x => x)调用以使基于语法的查询正常工作：

var sections = from el in xDoc.Descendants("Department")
                where el.Element("id").Value.Equals("001")
                select el.Elements("Section");

var rooms = from el in sections.SelectMany(x => x)
            where el.Element("SectionId").Value.Equals("001001")
            select el.Elements("Room");

var roomsList = (from el in rooms.SelectMany(x => x)
                    select new 
                    {
                        roomID = (string)el.Element("RoomID"),
                        owner = (string)el.Element("Owner")
                    }).ToList();
于 2013-08-16T08:46:51.830 回答
1

只是为了表明有很多方法可以给猫剥皮：

var xDoc = XDocument.Load(@"C:\TEST\TEST.XML");

var depts = from e in xDoc.Descendants("Department")
            where e.Element("id").Value.Equals("001")
            select e;

var sections = from e in depts.Descendants("Section")
            where e.Element("SectionId").Value.Equals("001001")
            select e;

var rooms = (from e in sections.Descendants("Room")
            select new //Room 
            {
                ID = (string)e.Element("RoomID"),
                Owner = (string)e.Element("Owner")
            }).ToList();
于 2013-08-16T10:11:51.013 回答
0

如果你改变：

select el.Element("Room");

至

select el.Elements("Room");
于 2013-08-16T08:22:30.190 回答
0

您只在中间查询中选择了一个房间，它应该是.Elements(...)（注意尾随s）：

        var rooms = from el in sections
                       where el.Element("SectionId").Value.Equals("001001")
                       select el.Elements("Room");

这同样适用于您的section查询。

于 2013-08-16T08:22:44.520 回答