C#按路径流式遍历XML节点的实用方法

<set>
  <fields>
    <field>
      <fieldname>rq</fieldname>
      <datatype>字符</datatype>
    </field>
    <field>
      <fieldname>djbh</fieldname>
      <datatype>字符</datatype>
    </field>
  </fields>
</set>

string xmlstr = File.ReadAllText("example.xml");

var fields = XmlStreamHelper.StreamElements(xmlstr, "set/fields/field");

Console.WriteLine("字段数量：" + fields.Count());
foreach (var f in fields)
{
    Console.WriteLine(f.Element("fieldname")?.Value);
}

字段数量：2
rq
djbh

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Xml;
using System.Xml.Linq;

public static class XmlStreamHelper
{
    /// <summary>
    /// 按路径流式遍历 XML 节点，路径用 / 分隔
    /// </summary>
    /// <param name="xmlstr">XML 字符串</param>
    /// <param name="xpath">节点路径，例如 "set/fields/field"</param>
    public static IEnumerable<XElement> StreamElements(string xmlstr, string xpath)
{
    if (string.IsNullOrWhiteSpace(xmlstr) || string.IsNullOrWhiteSpace(xpath))
        yield break;

    var nodes = xpath.Split('/');
    using var reader = XmlReader.Create(new StringReader(xmlstr), new XmlReaderSettings { IgnoreWhitespace = true, IgnoreComments = true });
    reader.MoveToContent();

    if (nodes.Length == 1)
    {
        if (XNode.ReadFrom(reader) is XElement el)
        {
            foreach (var e in el.Elements(xpath))
            {
                yield return e;
            }
        }
    }
    else
    {
        while (reader.Read())
        {
            if (reader.NodeType != XmlNodeType.Element) continue;

            if (reader.Name == nodes[0] && XNode.ReadFrom(reader) is XElement el)
            {
                foreach (var child in GetElementsRecursive(el, nodes, 1))
                    yield return child;
            }
        }
    }
}

    /// <summary>
    /// 递归获取子节点
    /// </summary>
    private static IEnumerable<XElement> GetElementsRecursive(XElement el, string[] nodes, int index)
    {
        if (index == nodes.Length - 1)
            return el.Elements(nodes[index]);

        var sub = el.Element(nodes[index]);
        return sub == null ? Enumerable.Empty<XElement>() : GetElementsRecursive(sub, nodes, index + 1);
    }
}