使用 LINQ 解析 XML 以获取子元素 [英] Parse XML with LINQ to get child elements

问题描述

<?xml version="1.0" standalone="yes"?>
<CompanyInfo>
     <Employee name="Jon" deptId="123">
      <Region name="West">
        <Area code="96" />
      </Region>
      <Region name="East">
        <Area code="88" />
      </Region>
     </Employee>
</CompanyInfo>  

public class Employee
{
    public string EmployeeName { get; set; }
    public string DeptId { get; set; }
    public List<string> RegionList {get; set;}
}

public class Region
{
    public string RegionName { get; set; }
    public string AreaCode { get; set; }
}

我正在尝试读取这个 XML 数据，到目前为止我已经尝试过:

I am trying to read this XML data, so far I have tried this:

XDocument xml = XDocument.Load(@"C:data.xml");
var xElement = xml.Element("CompanyInfo");
if (xElement != null)
    foreach (var child in xElement.Elements())
    {
        Console.WriteLine(child.Name);  
        foreach (var item in child.Attributes())
        {
            Console.WriteLine(item.Name + ": " + item.Value);
        }

        foreach (var childElement in child.Elements())
        {
            Console.WriteLine("--->" + childElement.Name);
            foreach (var ds in childElement.Attributes())
            {
                Console.WriteLine(ds.Name + ": " + ds.Value);
            }
            foreach (var element in childElement.Elements())
            {
                Console.WriteLine("------->" + element.Name);
                foreach (var ds in element.Attributes())
                {
                    Console.WriteLine(ds.Name + ": " + ds.Value);
                }
            }
        }                
    }

这使我能够获取每个节点，其属性名称和值，因此我可以将这些数据保存到数据库中的相关字段中，但这似乎是一个冗长的方式，并且不灵活，例如，如果 XML 结构发生变化，所有这些 foreach 语句都需要重新访问，那么这种方式也很难过滤数据，我需要编写某些 if 语句来过滤数据(例如，仅从 West 获取员工等...)

This enables me to get each node, its attribute name and value and so I can save these data into the relevant field in database, but this seems a long winded way and not flexible, for instance if the XML structure changes all those foreach statements needs revisiting, also it is difficult to filter the data this way, I need to write certain if statements to filter the data (e.g get employees from West only etc...)

我一直在寻找一种更灵活的方式，使用 linq，如下所示:

I was looking for a more flexible way, using linq, something like this:

List<Employees> employees =
              (from employee in xml.Descendants("CompanyInfo")
               select new employee
               {
                   EmployeeName = employee.Element("employee").Value,
                   EmployeeDeptId = ?? get data,
                   RegionName = ?? get data,
                   AreaCode = ?? get data,,
               }).ToList<Employee>();

但我不确定如何从子节点获取值并应用过滤(仅获取某些员工).这可能吗?任何帮助表示赞赏.

But I am not sure how I can get the values from the child nodes and apply the filtering (to get the certain employees only). Is this possible? Any help is appreciated.

谢谢

推荐答案

var employees = (from e in xml.Root.Elements("Employee")
                 let r = e.Element("Region")
                 where (string)r.Attribute("name") == "West"
                 select new Employee
                 {
                     EmployeeName = (string)e.Attribute("employee"),
                     EmployeeDeptId = (string)e.Attribute("deptId"),
                     RegionName = (string)r.Attribute("name"),
                     AreaCode = (string)r.Element("Area").Attribute("code"),
                 }).ToList();

但当 XML 文件结构发生变化时，仍需要修改查询.

But it will still require query revision when XML file structure changes.

编辑

查询每个员工的多个区域:

Query for multiple regions per employee:

var employees = (from e in xml.Root.Elements("Employee")
                 select new Employee
                 {
                     EmployeeName = (string)e.Attribute("employee"),
                     DeptId = (string)e.Attribute("deptId"),
                     RegionList = e.Elements("Region")
                                   .Select(r => new Region {
                                       RegionName = (string)r.Attribute("name"),
                                       AreaCode = (string)r.Element("Area").Attribute("code")
                                   }).ToList()
                 }).ToList();

然后，您可以仅筛选来自给定区域的员工列表:

You can then filter the list for employees from given region only:

var westEmployees = employees.Where(x => x.RegionList.Any(r => r.RegionName == "West")).ToList();

这篇关于使用 LINQ 解析 XML 以获取子元素的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！