基于XML中StopSeg节点获取对应I_TP40B1节点的XPath或C#实现求助

XPath 表达式 #

由于XML中StructuredText节点带有命名空间，提供两种写法：

方式1：忽略命名空间（简单快速） #

//Component[@Name='StopSeg']/../../../../following-sibling::*[local-name()='Token' and @Text=':=']/following-sibling::*[local-name()='Access']/*[local-name()='Symbol']/*[local-name()='Component']

方式2：带命名空间的严谨写法 #

需先注册命名空间（前缀设为st，对应http://www.siemens.com/automation/Openness/SW/NetworkSource/StructuredText/v3）：

//Component[@Name='StopSeg']/../../../../st:Token[@Text=':=']/following-sibling::st:Access/st:Symbol/st:Component

C# 代码实现 #

方法1：使用 XDocument（LINQ to XML） #

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

class Program
{
    static void Main()
    {
        string xmlContent = @"<Document>
    <SW.Blocks.FC ID=""0"">
        <ObjectList>
            <SW.Blocks.CompileUnit ID=""4"" CompositionName=""CompileUnits"">
                <AttributeList>
                    <NetworkSource>
                        <StructuredText xmlns=""http://www.siemens.com/automation/Openness/SW/NetworkSource/StructuredText/v3"">
                        <NewLine Num=""2"" UId=""116"" />
                        <Access Scope=""GlobalVariable"" UId=""117"">
                            <Symbol UId=""118"">
                              <Component Name=""TP40"" UId=""119"" />
                              <Token Text=""."" UId=""120"" />
                              <Component Name=""IN"" UId=""121"" />
                              <Token Text=""."" UId=""122"" />
                              <Component Name=""StopSeg"" UId=""123"" />
                              <Address Area=""None"" Type=""Bool"" BlockNumber=""3"" BitOffset=""3024"" Informative=""true"" />
                            </Symbol>
                        </Access>
                        <Blank Num=""29"" UId=""124"" />
                        <Token Text="":="" UId=""125"" />
                        <Blank Num=""1"" UId=""126"" />
                        <Access Scope=""GlobalVariable"" UId=""127"">
                        <Symbol UId=""128"">
                          <Component Name=""I_TP40B1"" UId=""129"" />
                          <Address Area=""Input"" Type=""Bool"" BitOffset=""1026"" Informative=""true"" />
                        </Symbol>
                        </Access>
                        <Token Text="";"" UId=""130"" />
                        <NewLine Num=""1"" UId=""131"" />
                    </StructuredText>
                    </NetworkSource>
                </AttributeList>
            </SW.Blocks.CompileUnit>
        </ObjectList>
    </SW.Blocks.FC>
</Document>";

        XDocument doc = XDocument.Parse(xmlContent);
        XNamespace stNs = "http://www.siemens.com/automation/Openness/SW/NetworkSource/StructuredText/v3";

        // 定位Name为StopSeg的Component节点
        var stopSegComponent = doc.Descendants("Component")
                                  .FirstOrDefault(c => (string)c.Attribute("Name") == "StopSeg");

        if (stopSegComponent != null)
        {
            // 找到所属的StructuredText父节点
            var structuredText = stopSegComponent.Ancestors(stNs + "StructuredText").FirstOrDefault();
            if (structuredText != null)
            {
                // 找到":="标记，再定位其后的Access节点下的Component
                var targetComponent = structuredText.Elements(stNs + "Token")
                                                   .FirstOrDefault(t => (string)t.Attribute("Text") == ":=")
                                                   ?.ElementsAfterSelf(stNs + "Access")
                                                   .FirstOrDefault()
                                                   ?.Element(stNs + "Symbol")
                                                   ?.Element(stNs + "Component");

                if (targetComponent != null)
                {
                    Console.WriteLine($"目标Component的Name值: {(string)targetComponent.Attribute("Name")}");
                }
                else
                {
                    Console.WriteLine("未找到对应的Component节点");
                }
            }
        }
    }
}

方法2：使用 XmlDocument #

using System;
using System.Xml;

class Program
{
    static void Main()
    {
        string xmlContent = @"<Document>
    <SW.Blocks.FC ID=""0"">
        <ObjectList>
            <SW.Blocks.CompileUnit ID=""4"" CompositionName=""CompileUnits"">
                <AttributeList>
                    <NetworkSource>
                        <StructuredText xmlns=""http://www.siemens.com/automation/Openness/SW/NetworkSource/StructuredText/v3"">
                        <NewLine Num=""2"" UId=""116"" />
                        <Access Scope=""GlobalVariable"" UId=""117"">
                            <Symbol UId=""118"">
                              <Component Name=""TP40"" UId=""119"" />
                              <Token Text=""."" UId=""120"" />
                              <Component Name=""IN"" UId=""121"" />
                              <Token Text=""."" UId=""122"" />
                              <Component Name=""StopSeg"" UId=""123"" />
                              <Address Area=""None"" Type=""Bool"" BlockNumber=""3"" BitOffset=""3024"" Informative=""true"" />
                            </Symbol>
                        </Access>
                        <Blank Num=""29"" UId=""124"" />
                        <Token Text="":="" UId=""125"" />
                        <Blank Num=""1"" UId=""126"" />
                        <Access Scope=""GlobalVariable"" UId=""127"">
                        <Symbol UId=""128"">
                          <Component Name=""I_TP40B1"" UId=""129"" />
                          <Address Area=""Input"" Type=""Bool"" BitOffset=""1026"" Informative=""true"" />
                        </Symbol>
                        </Access>
                        <Token Text="";"" UId=""130"" />
                        <NewLine Num=""1"" UId=""131"" />
                    </StructuredText>
                    </NetworkSource>
                </AttributeList>
            </SW.Blocks.CompileUnit>
        </ObjectList>
    </SW.Blocks.FC>
</Document>";

        XmlDocument doc = new XmlDocument();
        doc.LoadXml(xmlContent);
        XmlNamespaceManager nsMgr = new XmlNamespaceManager(doc.NameTable);
        nsMgr.AddNamespace("st", "http://www.siemens.com/automation/Openness/SW/NetworkSource/StructuredText/v3");

        // 通过XPath直接查询目标节点
        XmlNode targetNode = doc.SelectSingleNode("//Component[@Name='StopSeg']/../../../../st:Token[@Text=':=']/following-sibling::st:Access/st:Symbol/st:Component", nsMgr);

        if (targetNode != null)
        {
            Console.WriteLine($"目标Component的Name值: {targetNode.Attributes["Name"].Value}");
        }
        else
        {
            Console.WriteLine("未找到对应的Component节点");
        }
    }
}

内容的提问来源于stack exchange，提问作者Ankur