Question

使用C＃2.0和VIsualStudio2005

我正在尝试访问“MonitorResponseRecord”中的“DisplayName” 来自下面的XML文件：

    <Magellan xsi:schemaLocation="http://tempuri.org/XMLSchema.xsd ..\Schema\Configuration.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://tempuri.org/XMLSchema.xsd">
      <SchemaVersion>1.0</SchemaVersion>
          <MonitorScope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" id="CleanStationChemicalManifoldFeed5" xmlns="http://tempuri.org/XMLSchema.xsd">
            <PersonalSafety>
              <MonitorResponseRecord Enabled="true" DisplayName="ChemicalManifoldFeed5ControllerFault">
                <ExpressionMonitor>
                  <Expression>(ChemicalManifold.Feed5.DispenseValve = Open) and ((ChemicalManifold.Feed5.ViolatedRegion = HighProcess) or (ChemicalManifold.Feed5.ViolatedRegion = LowProcess) or (ChemicalManifold.Feed5.ViolatedRegion = Minimum))</Expression>
                  <TestInterval>0.1</TestInterval>
                  <MinimumTimeBetweenResponses>5</MinimumTimeBetweenResponses>
                </ExpressionMonitor>
                <Response>
                  <PostAlarm>
                    <AlarmName>ChemicalManifold_Feed5_ControllerFault</AlarmName>
                    <Parameter1 />
                    <Parameter2>Alarm Region = {ChemicalManifold.Feed5.ViolatedRegion}</Parameter2>
                    <Parameter3>{RecipeName}-{StepName}</Parameter3>
                    <Parameter4>FlowSetpoint = {ChemicalManifold.Feed5.Setpoint}-LPM, ActualFlow = {ChemicalManifold.Feed5.FlowMeter}-LPM</Parameter4>
                  </PostAlarm>
                  <ResponseEvent>
                    <TargetResource />
                    <Event>PA</Event>
                    <Reason>ChemicalSupply</Reason>
                  </ResponseEvent>
                </Response>
              </MonitorResponseRecord>
            </PersonalSafety>
            <PersonalSafety>
              <MonitorResponseRecord Enabled="true" DisplayName = "PressureValveFailure">
           ...
            ...                
             ...and soon

我当前的C＃尝试如下，但是当我尝试XmlDocument.Load("");

时，它总是挂断

                XmlDocument doc = new XmlDocument();
                doc.Load("../UMC0009.Configuration.Root.xml");
                string attrVal = doc.SelectSingleNode("MonitorResponseRecord/@DisplayName").Value;

BUUUUT不会工作：/任何帮助吗？

更新

我收到的异常如下，并在doc.Load（“...”）行发生：

{"Namespace Manager or XsltContext needed. This query has a prefix, variable, or user-defined function."} System.Exception {System.Xml.XPath.XPathException}

Answer 1

您的XPath查询将相对于文档根目录：

doc.SelectSingleNode("MonitorResponseRecord/@DisplayName")

要使其在doc前缀中的任何位置搜索，请使用双斜杠：

doc.SelectSingleNode("//MonitorResponseRecord/@DisplayName")

如果仍然无效，我会在两个根节点上删除所有这些命名空间声明后尝试上面的例子。

否则，使用命名空间声明，您可能会发现需要定义XML命名空间映射并在XPath中使用前缀，如：

XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc.NameTable);
nsmgr.AddNamespace("x", "http://tempuri.org/XMLSchema.xsd");

doc.SelectSingleNode("//x:MonitorResponseRecord/@DisplayName")

Answer 2

怎么样：

    XmlDocument doc = new XmlDocument();
    doc.Load("UMC0009.Configuration.Root.xml");

    XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc.NameTable);
    nsmgr.AddNamespace("ns", "http://tempuri.org/XMLSchema.xsd");
    string attrVal = doc.SelectSingleNode("//ns:MonitorResponseRecord/@DisplayName", nsmgr).Value;

使用命名空间管理器，指定您的命名空间URI并在XPath中使用它。它对我有用。

C＃：读取XML属性

使用C＃2.0和VIsualStudio2005

更新

2 个答案: