使用 XmlDocument 从有或没有命名空间的 xml 文件中读取 [英] Read from xml files with or without a namespace using XmlDocument

问题描述

我有一些代码使用 XmlDocument 从具有命名空间的 xml 文件中读取.我的挑战是我现在正在读取硬编码的文件的命名空间，我将它传递给 XmlNamespaceManager.我想为我的方法更灵活一点.从任何类型的 xml 文件中读取.如果它有命名空间，则使用命名空间管理器来读取元素，而无需对命名空间进行硬编码.如果文件没有命名空间，然后去前进，只需解析它.下面是我所做的.

I have some code that reads from xml files with a namespace using XmlDocument.My challenge is that i have the namespace of the file i'm reading hard coded for now and i pass that to the XmlNamespaceManager.I would like for my approach to be a little more flexible.To read from any kind of xml file.If it has a namespace,then use the namespace manager to read the elements without hard coding the namespace.If the file doesn't have a namespace,then go ahead and just parse it.Below is what I've done.

xmldoc = new XmlDocument ();
xmldoc.Load (fileLocation);


XmlNamespaceManager nameSpaceManager = new XmlNamespaceManager(xmldoc.NameTable);

nameSpaceManager.AddNamespace ("ns","http://schemas.sample.data.org/2005");

XmlNodeList nodeList = xmldoc.SelectNodes("/ns:Demo/ns:Items",  nameSpaceManager);
if (nodeList != null) 
{
    foreach (XmlNode childNode in nodeList) 
    {
        string first = childNode.SelectSingleNode ("ns:First", nameSpaceManager).InnerText;
        string second= childNode.SelectSingleNode ("ns:Second", nameSpaceManager).InnerText;
        string third = childNode.SelectSingleNode ("ns:Third", nameSpaceManager).InnerText;
    }
}

这是我正在使用的示例 xml 文件

Here's the sample xml file i'm using

<Demo xmlns:i="http://www.justasample.com" xmlns="http://schemas.sample.data.org/2005">
 <Items>

  <First>first</First>
  <Second>second</Second>
  <Third>third</Third>

  </Items>

</Demo>

推荐答案

您可以考虑以下选项:

1. 确定文档是否包含命名空间，并根据它构造 xpath 查询
2. 使用与命名空间无关的 xpath，例如 local-name()，这将忽略命名空间

选项 1

var xmlDoc = new XmlDocument();
xmlDoc.Load(fileLocation);
//determine  whether document contains namespace
var namespaceName = "ns";
var namespacePrefix = string.Empty;
XmlNamespaceManager nameSpaceManager = null;
if (xmlDoc.FirstChild.Attributes != null)
{
    var xmlns = xmlDoc.FirstChild.Attributes["xmlns"];
    if (xmlns != null)
    {
          nameSpaceManager = new XmlNamespaceManager(xmlDoc.NameTable);
          nameSpaceManager.AddNamespace(namespaceName, xmlns.Value);
          namespacePrefix = namespaceName + ":";
    }
}

XmlNodeList nodeList = xmlDoc.SelectNodes(string.Format("/{0}Demo/{0}Items",namespacePrefix), nameSpaceManager);
if (nodeList != null)
{
    foreach (XmlNode childNode in nodeList)
    {
       string first = childNode.SelectSingleNode(namespacePrefix + "First", nameSpaceManager).InnerText;
       string second = childNode.SelectSingleNode(namespacePrefix + "Second", nameSpaceManager).InnerText;
       string third = childNode.SelectSingleNode(namespacePrefix +  "Third", nameSpaceManager).InnerText;
     }
 }

选项 2

XmlNodeList nodeList = xmlDoc.SelectNodes("/*[local-name() = 'Demo']/*[local-name() = 'Items']");
if (nodeList != null)
{
    foreach (XmlNode childNode in nodeList)
    {    
        string first = childNode.SelectSingleNode("*[local-name() = 'First']").InnerText;
        string second = childNode.SelectSingleNode("*[local-name() = 'Second']").InnerText;
        string third = childNode.SelectSingleNode("*[local-name() = 'Third']").InnerText;
     }
}

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