問題描述

<?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; }
}

我正在嘗試讀取這個 XML 數據，到目前為止我已經嘗試過:

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);
                }
            }
        }                
    }

這使我能夠獲取每個節點，其屬性名稱和值，因此我可以將這些數據保存到數據庫中的相關字段中，但這似乎是一個冗長的方式，并且不靈活，例如，如果 XML 結構發生變化，所有這些 foreach 語句都需要重新訪問，那么這種方式也很難過濾數據，我需要編寫某些 if 語句來過濾數據(例如，僅從 West 獲取員工等...)

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...)

我一直在尋找一種更靈活的方式，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>();

但我不確定如何從子節點獲取值并應用過濾(僅獲取某些員工).這可能嗎?任何幫助表示贊賞.

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.

謝謝

推薦答案

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();

但當 XML 文件結構發生變化時，仍需要修改查詢.

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

編輯

查詢每個員工的多個區域:

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，您可以僅篩選來自給定區域的員工列表:

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();

這篇關于使用 LINQ 解析 XML 以獲取子元素的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！