如何在c#中读取和解析XML文件?
有很多方法,一些:
XmlSerializer。使用带有目标模式的类 如果您想读取,请使用XmlSerializer 将Xml中的数据加载到 类的实例。 linq2xml XmlTextReader。 XmlDocument XPathDocument(只读访问)
XmlDocument从字符串或文件中读取XML。
using System.Xml;
XmlDocument doc = new XmlDocument();
doc.Load("c:\\temp.xml");
or
doc.LoadXml("<xml>something</xml>");
然后在它下面找到一个节点,就像这样
XmlNode node = doc.DocumentElement.SelectSingleNode("/book/title");
or
foreach(XmlNode node in doc.DocumentElement.ChildNodes){
string text = node.InnerText; //or loop through its children as well
}
然后像这样读取节点内的文本
string text = node.InnerText;
或者读取属性
string attr = node.Attributes["theattributename"]?.InnerText
总是检查Attributes["something"]是否为空,因为如果属性不存在,它将为空。
LINQ to XML示例:
// Loading from a file, you can also load from a stream
var xml = XDocument.Load(@"C:\contacts.xml");
// Query the data and write out a subset of contacts
var query = from c in xml.Root.Descendants("contact")
where (int)c.Attribute("id") < 4
select c.Element("firstName").Value + " " +
c.Element("lastName").Value;
foreach (string name in query)
{
Console.WriteLine("Contact's Full Name: {0}", name);
}
参考:LINQ到XML在MSDN
下面是我写的一个读取xml站点地图的应用程序:
using System;
using System.Collections.Generic;
using System.Windows.Forms;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Data;
using System.Xml;
namespace SiteMapReader
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Please Enter the Location of the file");
// get the location we want to get the sitemaps from
string dirLoc = Console.ReadLine();
// get all the sitemaps
string[] sitemaps = Directory.GetFiles(dirLoc);
StreamWriter sw = new StreamWriter(Application.StartupPath + @"\locs.txt", true);
// loop through each file
foreach (string sitemap in sitemaps)
{
try
{
// new xdoc instance
XmlDocument xDoc = new XmlDocument();
//load up the xml from the location
xDoc.Load(sitemap);
// cycle through each child noed
foreach (XmlNode node in xDoc.DocumentElement.ChildNodes)
{
// first node is the url ... have to go to nexted loc node
foreach (XmlNode locNode in node)
{
// thereare a couple child nodes here so only take data from node named loc
if (locNode.Name == "loc")
{
// get the content of the loc node
string loc = locNode.InnerText;
// write it to the console so you can see its working
Console.WriteLine(loc + Environment.NewLine);
// write it to the file
sw.Write(loc + Environment.NewLine);
}
}
}
}
catch { }
}
Console.WriteLine("All Done :-)");
Console.ReadLine();
}
static void readSitemap()
{
}
}
}
粘贴箱代码 http://pastebin.com/yK7cSNeY
public void ReadXmlFile()
{
string path = HttpContext.Current.Server.MapPath("~/App_Data"); // Finds the location of App_Data on server.
XmlTextReader reader = new XmlTextReader(System.IO.Path.Combine(path, "XMLFile7.xml")); //Combines the location of App_Data and the file name
while (reader.Read())
{
switch (reader.NodeType)
{
case XmlNodeType.Element:
break;
case XmlNodeType.Text:
columnNames.Add(reader.Value);
break;
case XmlNodeType.EndElement:
break;
}
}
}
可以避免使用第一个语句,只在XmlTextReader的构造函数中指定路径名。
您可以使用数据集读取XML字符串。
var xmlString = File.ReadAllText(FILE_PATH);
var stringReader = new StringReader(xmlString);
var dsSet = new DataSet();
dsSet.ReadXml(stringReader);
发布这篇文章是为了提供信息。
There are different ways, depending on where you want to get. XmlDocument is lighter than XDocument, but if you wish to verify minimalistically that a string contains XML, then regular expression is possibly the fastest and lightest choice you can make. For example, I have implemented Smoke Tests with SpecFlow for my API and I wish to test if one of the results in any valid XML - then I would use a regular expression. But if I need to extract values from this XML, then I would parse it with XDocument to do it faster and with less code. Or I would use XmlDocument if I have to work with a big XML (and sometimes I work with XML's that are around 1M lines, even more); then I could even read it line by line. Why? Try opening more than 800MB in private bytes in Visual Studio; even on production you should not have objects bigger than 2GB. You can with a twerk, but you should not. If you would have to parse a document, which contains A LOT of lines, then this documents would probably be CSV.
我写这条评论,是因为我看到了大量使用XDocument的示例。XDocument不适用于大型文档,或者当您只想验证内容是否为XML有效时。如果希望检查XML本身是否有意义,那么需要Schema。
我对建议的答案也投了反对票,因为我相信它本身就需要上述信息。假设我需要验证200M的XML是否有效,每小时10次。XDocument会浪费大量的资源。
prasanna venkatesh还指出,您可以尝试将字符串填充到数据集,它也将指示有效的XML。
如果您想从XML文件中检索特定的值
XmlDocument _LocalInfo_Xml = new XmlDocument();
_LocalInfo_Xml.Load(fileName);
XmlElement _XmlElement;
_XmlElement = _LocalInfo_Xml.GetElementsByTagName("UserId")[0] as XmlElement;
string Value = _XmlElement.InnerText;
下面是另一种使用Cinchoo ETL的方法,它是一个开源库,可以用很少的代码行解析xml文件。
using (var r = ChoXmlReader<Item>.LoadText(xml)
.WithXPath("//item")
)
{
foreach (var rec in r)
rec.Print();
}
public class Item
{
public string Name { get; set; }
public string ProtectionLevel { get; set; }
public string Description { get; set; }
}
样本提琴:https://dotnetfiddle.net/otYq5j
免责声明:我是这个库的作者。
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