c# - 使用 XmlTextReader 获取 XML 的子元素

Question

我有以下 XML：

<UpsHistory>
 <UpsSettings>
  <Filename>modbusevent.xml</Filename>
  <FileDate>04.02.1970</FileDate>
  <FileTime>00:05:39</FileTime>
  <Type>ENERTRONIC I 3-3 20kVA</Type>
  <Location></Location>
  <Phases>3</Phases>
  <UpsContact>
   <Company></Company>
   <Department></Department>
   <Contact></Contact>
   <City></City>
   <Street></Street>
   <Phone></Phone>
  </UpsContact>
 </UpsSettings>
 <UpsData id="1">
  <Date>09.08.2012</Date>
  <Time>12:05:53.52</Time>
  <EventCode>574</EventCode>
  <EventState>A</EventState>
  <EventText><![CDATA[IGBT - DRIVERBOARD FAILURE]]></EventText>
  <EventAction>/upsexe.cgi?cmd=2003&amp;p1=574&amp;reload=/mbevents.cgi&amp;wait=5</EventAction>
 </UpsData>
 <UpsData id="2">
  <Date>09.08.2012</Date>
  <Time>11:23:08.88</Time>
  <EventCode>606</EventCode>
  <EventState>E</EventState>
  <EventText><![CDATA[BYPASS VOLTAGE FAILURE]]></EventText>
  <EventAction>/upsexe.cgi?cmd=2003&amp;p1=606&amp;reload=/mbevents.cgi&amp;wait=5</EventAction>
 </UpsData>
 <UpsData id="3">
  <Date>09.08.2012</Date>
  <Time>11:23:07.06</Time>
  <EventCode>1000</EventCode>
  <EventState>E</EventState>
  <EventText><![CDATA[CUSTOMER RELAY 1 ON]]></EventText>
  <EventAction>/upsexe.cgi?cmd=2003&amp;p1=1000&amp;reload=/mbevents.cgi&amp;wait=5</EventAction>
 </UpsData>
 <UpsData id="4">
  <Date>09.08.2012</Date>
  <Time>11:23:06.97</Time>
  <EventCode>1003</EventCode>
  <EventState>E</EventState>
  <EventText><![CDATA[CUSTOMER RELAY 2 OFF]]></EventText>
  <EventAction>/upsexe.cgi?cmd=2003&amp;p1=1003&amp;reload=/mbevents.cgi&amp;wait=5</EventAction>
 </UpsData>

...

<UpsData id="602">
  <Date>08.09.2012</Date>
  <Time>11:06:13.84</Time>
  <EventCode>606</EventCode>
  <EventState>E</EventState>
  <EventText><![CDATA[BYPASS VOLTAGE FAILURE]]></EventText>
  <EventAction>/upsexe.cgi?cmd=2003&amp;p1=606&amp;reload=/mbevents.cgi&amp;wait=5</EventAction>
 </UpsData>
</UpsHistory>

我想获取所有带有子元素值的 UpsData 元素，但我只有 UpsData 元素 id：

流 sw = CopyAndClose(response.GetResponseStream());

XmlTextReader rdr = new XmlTextReader(sw);
                            while (rdr.Read())
                            {
                                if (rdr.IsStartElement())
                                {
                                    if (rdr.NodeType == XmlNodeType.Element)
                                    {
                                        if (rdr.Name == "UpsData")
                                        {
                                            rdr.MoveToAttribute("id");
                                            if (rdr.Name == "Date")
                                            {
                                                ConsoleInfo(rdr.Value);
                                            }
                                        }
                                    }
                                }
                            }

如何获取子元素值？谢谢！

Answer 1

如果您可以使用XmlDocument或XmlPathNagivator，请考虑使用 XPath。例如：

using System.Xml;

...

XmlDocument xmlDocument = new XmlDocument();
xmlDocument.LoadXml(xml);
foreach (XmlNode xmlNode in 
    xmlDocument.DocumentElement.SelectNodes("UpsData/@id[/*]"))
{
    // Do something, for example:
    Console.Out.WriteLine("Value: " + xmlNode.Value);
}

XPath"UpsData/@id[/*]"表示查找名为“UpsData”的子节点和具有子节点的“id”属性并返回“id”属性。