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c# - 如何使用 XmlDocument 解析带有命名空间的 XML

问题描述

我在https://dotnetfiddle.net/ 上运行此代码 https://gist.github.com/ccumaya/10b1a58efe06c1f8080045457c5cf4b8 （该站点现在无法获取链接，所以我使用 gist。）

我的目的是获取 XML 文件中的 GPS 点，但是XPath 

'/gpx/trk/trkseg/trkpt'

不起作用。我不知道哪里出错了，但我正在使用XPath 

'//*'

并得到 1439 个结果。我需要帮助，谢谢你的指导。

xml结构如下。

<gpx xmlns="http://www.topografix.com/GPX/1/1" xmlns:gpxx="http://www.garmin.com/xmlschemas/GpxExtensions/v3" xmlns:gpxtrkx="http://www.garmin.com/xmlschemas/TrackStatsExtension/v1" xmlns:wptx1="http://www.garmin.com/xmlschemas/WaypointExtension/v1" xmlns:gpxtpx="http://www.garmin.com/xmlschemas/TrackPointExtension/v1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" creator="GPSMAP 64ST TWN" version="1.1" xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd http://www.garmin.com/xmlschemas/GpxExtensions/v3 http://www8.garmin.com/xmlschemas/GpxExtensionsv3.xsd http://www.garmin.com/xmlschemas/TrackStatsExtension/v1 http://www8.garmin.com/xmlschemas/TrackStatsExtension.xsd http://www.garmin.com/xmlschemas/WaypointExtension/v1 http://www8.garmin.com/xmlschemas/WaypointExtensionv1.xsd http://www.garmin.com/xmlschemas/TrackPointExtension/v1 http://www.garmin.com/xmlschemas/TrackPointExtensionv1.xsd">
  <metadata>
    <link href="http://www.garmin.com">
      <text>Garmin International</text>
    </link>
    <time>2018-10-05T09:21:31Z</time>
  </metadata>
  <trk>
    <name>2018-10-05 17:21:26</name>
    <extensions>
      <gpxx:TrackExtension>
        <gpxx:DisplayColor>Cyan</gpxx:DisplayColor>
      </gpxx:TrackExtension>
      <gpxtrkx:TrackStatsExtension>
        <gpxtrkx:Distance>1033</gpxtrkx:Distance>
        <gpxtrkx:TotalElapsedTime>996</gpxtrkx:TotalElapsedTime>
        <gpxtrkx:MovingTime>870</gpxtrkx:MovingTime>
        <gpxtrkx:StoppedTime>86</gpxtrkx:StoppedTime>
        <gpxtrkx:MovingSpeed>1</gpxtrkx:MovingSpeed>
        <gpxtrkx:MaxSpeed>2</gpxtrkx:MaxSpeed>
        <gpxtrkx:MaxElevation>207</gpxtrkx:MaxElevation>
        <gpxtrkx:MinElevation>189</gpxtrkx:MinElevation>
        <gpxtrkx:Ascent>17</gpxtrkx:Ascent>
        <gpxtrkx:Descent>5</gpxtrkx:Descent>
        <gpxtrkx:AvgAscentRate>0</gpxtrkx:AvgAscentRate>
        <gpxtrkx:MaxAscentRate>0</gpxtrkx:MaxAscentRate>
        <gpxtrkx:AvgDescentRate>0</gpxtrkx:AvgDescentRate>
        <gpxtrkx:MaxDescentRate>-0</gpxtrkx:MaxDescentRate>
        </gpxtrkx:TrackStatsExtension>
      </extensions>
      <trkseg>
        <trkpt lat="25.0312615000" lon="121.3505846635">
        <ele>189.04</ele>
        <time>2018-10-05T09:04:55Z</time>
      </trkpt>
      <trkpt lat="25.0312520284" lon="121.3505897764">
        <ele>189.04</ele>
        <time>2018-10-05T09:04:57Z</time>
        </trkpt>
      <trkpt lat="25.0312457420" lon="121.3506018464">
        <ele>196.43</ele>
        <time>2018-10-05T09:04:59Z</time>
      </trkpt>
      <trkpt lat="25.0312426407" lon="121.3506035227">
        <ele>196.42</ele>
        <time>2018-10-05T09:05:01Z</time>
      </trkpt>
    </trkseg>
  </trk>
</gpx>

感谢您的帮助

标签： c#asp.netxmlxpathxml-parsing

解决方案

如果您只需要纬度和经度，您可以使用 xml linq 轻松获取它，代码如下：

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

namespace ConsoleApplication1
{
    class Program
    {
        const string FILENAME = @"c:\temp\gps.xml";
        static void Main(string[] args)
        {
            XDocument doc = XDocument.Load(FILENAME);
            XElement root = doc.Root;
            XNamespace ns = root.GetDefaultNamespace();

            var results = doc.Descendants(ns + "trkpt").Select(x => new
            {
                lat = x.Attribute("lat"),
                lon = x.Attribute("lon"),
                ele = (decimal)x.Element(ns + "ele"),
                time = (DateTime)x.Element(ns + "time")
            }).ToList();

        }
    }
}

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