教程

https://www.w3schools.com/xml/xpath_nodes.asp

节点之间的关系

Parent，Children，Siblings，Ancestors，Descendants

qutoric

最新的online工具 http://www.qutoric.com/xslt/analyser/xpathtool.html

旧版的 http://qutoric.com/sketchpath/xpath-editor.html

visual studio的插件

https://github.com/uli-weltersbach/XPathTools

https://github.com/uli-weltersbach/XPathTools/wiki 使用方法

Copy value-based XPath

https://github.com/uli-weltersbach/XPathTools/wiki/Copying-XPaths#copy-value-based-xpath

在Distinct XPath中新增一个key,这样可以拿到appSettings下面的key/value的xpath

/configuration/appSettings/add[@key='OutputRuleWebPartExecutionTimeElapse']/@key

<add key="OutputRuleWebPartExecutionTimeElapse" value="False" />

将鼠标放在add上面，右键，选择copy xpath,然后找到第三个

得到的路径 /configuration/appSettings/add[@key='OutputRuleWebPartExecutionTimeElapse']

这个node的OuterXml是:<add key="OutputRuleWebPartExecutionTimeElapse" value="False" />

这个node的value是null

将鼠标放在value上面，选择copy xpath,然后找到第三个

得到的路径 /configuration/appSettings/add[@key='OutputRuleWebPartExecutionTimeElapse']/@value

这个node的OuterXml是：value="False"

这个node的value是: False

 [Test]
        public void XPathTest()
        {
            var path1 = "/configuration/appSettings/add[@key='OutputRuleWebPartExecutionTimeElapse']";
            var path2 = "/configuration/appSettings/add[@key='OutputRuleWebPartExecutionTimeElapse']/@value";
           
            var desktopPath = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
            var fileName = "test.xml";
            var filePath = Path.Combine(desktopPath, fileName);
            var doc = new XmlDocument();
            doc.Load(filePath);
            var node1 = doc.SelectSingleNode(path1);
            var node2= doc.SelectSingleNode(path2);
            Console.WriteLine(node1.OuterXml);
            Console.WriteLine(node2.OuterXml);
            Console.WriteLine(node2.Value);
        }

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <appSettings>
    <add key="OutputRuleWebPartExecutionTimeElapse" value="False" />
  </appSettings>
</configuration>

多种方法，通过C#移除xmlnode

https://stackoverflow.com/questions/6500989/deleting-xml-using-a-selected-xpath-and-a-for-loop

XmlDocument document = new XmlDocument();
document.Load(fileName);

XmlNode node = document.SelectSingleNode("Elements/Element1");
node.ParentNode.RemoveChild(node);

document.Save(fileName);