得到“<kml：.”在任何地方，更新Kml文件

Question

我正在读取一个Kml文件，更改placemarks的名称，并再次保存它。

var KmlFile = XDocument.Load("C:\\Inetpub\\wwwroot\\GeotagService\\Kml\\Photographs.kml");

XNamespace KmlNamespace = "http://www.opengis.net/kml/2.2";

// find the Placemarks in the Photos folder
IEnumerable<XElement> Placemarks = KmlFile.Element(KmlNamespace + "kml").Element(KmlNamespace + "Document").Element(KmlNamespace + "Folder").Elements(KmlNamespace + "Placemark");

foreach (XElement p in Placemarks){
    p.Element(KmlNamespace + "name").Value = "testing";
}

KmlFile.Save("C:\\Inetpub\\wwwroot\\GeotagService\\Kml\\Photographs.kml");

但是，当我保存它时，每个元素都以<kml:作为前缀，如下所示：

<kml:Folder>
  <kml:name>Photos</kml:name>
  <kml:open>1</kml:open>
  <kml:Placemark>
    <kml:name>testing</kml:name>
    <kml:LookAt>
      <kml:longitude>-10.02717694938161</kml:longitude>
      <kml:latitude>53.48672543547379</kml:latitude>
      <kml:altitude>0</kml:altitude>
    </kml:LookAt>
    <kml:styleUrl>#msn_ylw-pushpin1</kml:styleUrl>
    <kml:Point>
       <kml:coordinates>-10.02867619360582,53.48651240326751,0</kml:coordinates>
    </kml:Point>
 </kml:Placemark>...

Tomalak对关于空白xmlns的问题的评论给了我一个线索，可能是文档的名称空间和元素之间的不一致，但我无法理解我是如何做到的。有人知道吗？

编辑：原始文档(部分)：

    <?xml version="1.0" encoding="UTF-8"?>
    <kml xmlns="http://www.opengis.net/kml/2.2" xmlns:gx="http://www.google.com/kml/ext/2.2" xmlns:kml="http://www.opengis.net/kml/2.2" xmlns:atom="http://www.w3.org/2005/Atom">
    <Document>
        <name>Connemara.net Photographs</name>
        <open>1</open>
        <Style id="sh_ylw-pushpin0">
            <IconStyle>
                <scale>1.3</scale>
                <Icon>
                    <href>http://maps.google.com/mapfiles/kml/pushpin/ylw-pushpin.png</href>
                </Icon>
                <hotSpot x="20" y="2" xunits="pixels" yunits="pixels"/>
            </IconStyle>
        </Style>
        <Folder>
            <name>Photos</name>
            <open>1</open>
            <Placemark>
                <name>Id:579</name>
                <LookAt>
                    <longitude>-10.02717694938161</longitude>
                    <latitude>53.48672543547379</latitude>
                    <altitude>0</altitude>
                    <range>213.2931913230747</range>
                    <tilt>75.17546328115256</tilt>
                    <heading>69.89736514305363</heading>
                    <altitudeMode>relativeToGround</altitudeMode>
                    <gx:altitudeMode>relativeToSeaFloor</gx:altitudeMode>
                </LookAt>
                <styleUrl>#msn_ylw-pushpin1</styleUrl>
                <Point>
                    <coordinates>-10.02867619360582,53.48651240326751,0</coordinates>
                </Point>
            </Placemark>
...
</Folder>
</Document>
</kml>

Answer 1

明白了-问题是原始文档的开头是这样的：

 <kml xmlns="http://www.opengis.net/kml/2.2" 
      xmlns:gx="http://www.google.com/kml/ext/2.2" 
      xmlns:kml="http://www.opengis.net/kml/2.2" 
      xmlns:atom="http://www.w3.org/2005/Atom">

LINQ看到KML命名空间有一个特定的别名，所以使用它。如果删除该属性，它可以正常工作：

var explicitNs = KmlFile.Root.Attribute(XNamespace.Xmlns + "kml");
if (explicitNs != null)
{
    explicitNs.Remove();
}

Answer 2

您需要使用命名空间管理器。下面是一个使用XPath选择必要标记并更新其值的示例：

using System;
using System.Xml;
using System.Xml.Linq;
using System.Xml.XPath;

class Program
{
    static void Main(string[] args)
    {
        var kml = XDocument.Load("test.kml");
        var ns = new XmlNamespaceManager(new NameTable());
        ns.AddNamespace("kml", "http://www.opengis.net/kml/2.2");
        var names = kml.XPathSelectElements("//kml:Placemark/kml:name", ns);
        foreach (var name in names)
        {
            name.Value = "testing";
        }
        kml.Save("test.kml");
    }
}