Question

我是xml的新手，我不知道如何从xml文件中读取/获取值：

<?xml version="1.0" encoding="utf-8" ?>
<Jeopardy>
  <category name = 'People in Computing'>
<first points = '100' answer = 'Alan Turing'>Known as the questioner of the human   mind, this man is known for helping tell humans and computers apart.</first>
<second points = '200' answer = 'Grace Hopper'>This female pioneer of the COBOL computer programming language was an Admiral in the US Navy.</second>
<third points = '300' answer = 'Tim Berners-Lee'>Called the father of the world wide web, this man is the director of the W3C.</third>
<fourth points = '400' answer = 'Lawrence Lessig'>An American academic and political activist who founded the Creative Commons, this man lobbies for reduced legal restrictions on copyrights and trademarks in the technology sector.</fourth>
<fifth points = '500' answer = 'Ada Lovelace'>This woman, known as the world's first computer programmer was also a Countess.</fifth>
  </category>
</Jeopardy>

抱歉格式糟糕，无法正确使用。

首先，我尝试在XDocument结果中加载此文件，“非空白空间无法添加到内容”异常，但如果加载到XmlDocument中则不会发生。

我的代码试图获取名称值：

        string fileName = @"C:\Users\Kara\documents\visual studio 2010\Projects\Final Project\Final Project\Jeopardy.xml";

        XmlDocument doc = new XmlDocument();

        doc.Load(fileName);

        List<string> categories = new List<string>();

        XmlNodeList nList = doc.SelectNodes("/category/name");

        foreach (XmlNode node in nList)
        {
            categories.Add(node.ToString());
        }

可悲的是，调试nList的计数为零，我无法弄清楚原因。我已经尝试过在这里看到很多问题和其他地方的教程，我只是感到沮丧。我如何从名称和其他节点中获取值？有人可以解释一下吗？也许为什么我用XDocument得到非空格错误？

Answer 1

doc.SelectNodes("/category/name")

您没有找到任何节点，因为1）第一个节点是Jeopardy，而不是category和2）name是类别的属性而不是子元素。

尝试：doc.SelectNodes("/Jeopardy/category/@name")

像这样：

foreach (XmlNode node in nList) {
  categories.Add(node.Value);
}

Answer 2

确保文件的编码与文档加载方法所需的编码相匹配。通常UTF8是XML文件的首选编码。

如上所述，您可以使用：

doc.SelectNodes("/Jeopardy/category/name");

或

doc.SelectNodes("//category/name");

或

doc.SelectNodes("//name");

Answer 3

您需要打开XML文档

 XmlDocument _document = new XmlDocument();
    byte[] bytes = File.ReadAllBytes(filePath);
   string xml = Encoding.UTF8.GetString(bytes);
    try
    {
    _document.LoadXml(xml);
    }
    catch (XmlException e)
    {
    //exception handling
    }                  

    var doc = (XmlDocument)_document.CloneNode(true);

    XmlNode node = doc.GetElementsByTagName("your child node name");

一旦你获得了节点，你就可以用它做必要的事情

使用C＃从xml文件获取值

3 个答案: