元素名称中带有冒号的元素的 Xpath

Question

我的 xml 是

<?xml version="1.0" encoding="utf-8"?>
<EntityDescriptor ID="_2d6175bd-f939-49f2-a980-db4179f32074" entityID="https://server1.domain.com:xx3/yyy/" xmlns="urn:oasis:names:tc:SAML:2.0:metadata">
  <RoleDescriptor xsi:type="fed:ApplicationServiceType" xmlns:fed="http://docs.oasis-open.org/wsfed/federation/200706" protocolSupportEnumeration="http://docs.oasis-open.org/wsfed/federation/200706" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <fed:ClaimTypesRequested>
      <auth:ClaimType Uri="http://schemas.microsoft.com/ws/2008/06/identity" Optional="true" xmlns:auth="http://docs.oasis-open.org/wsfed/authorization/200706" />
    </fed:ClaimTypesRequested>
    <fed:TargetScopes>
      <EndpointReference xmlns="http://www.w3.org/2005/08/addressing">
        <Address>https://baarnntl1/</Address>
      </EndpointReference>
    </fed:TargetScopes>
    <fed:PassiveRequestorEndpoint>
      <EndpointReference xmlns="http://www.w3.org/2005/08/addressing">
        <Address>https://baarnntl1/</Address>
      </EndpointReference>
    </fed:PassiveRequestorEndpoint>
  </RoleDescriptor>
</EntityDescriptor>

我想更改地址元素值

XmlDocument fedMetaDocument = new XmlDocument();
fedMetaDocument.Load(federatedMetadataFile);
XmlNamespaceManager mgr = new XmlNamespaceManager(fedMetaDocument.NameTable);
mgr.AddNamespace("fed", "http://docs.oasis-open.org/wsfed/federation/200706");

foreach (XmlNode targetScopeNode in fedMetaDocument.SelectNodes("TargetScopes/EndpointReference/Address", mgr))
{
    targetScopeNode.Value = tsakListUrl;
}
foreach (XmlNode PassiveRequestorEndpointNode in fedMetaDocument.SelectNodes("TargetScopes/EndpointReference/Address", mgr))
{
    PassiveRequestorEndpointNode.Value = tsakListUrl;
}

我收到错误

  System.Xml.XPath.XPathException was unhandled by user code
  Message=Expression must evaluate to a node-set.
  Source=System.Xml
  StackTrace:
       at MS.Internal.Xml.XPath.XPathParser.ParseNodeTest(AstNode qyInput, AxisType axisType, XPathNodeType nodeType)
       at MS.Internal.Xml.XPath.XPathParser.ParseStep(AstNode qyInput)
       at MS.Internal.Xml.XPath.XPathParser.ParseRelativeLocationPath(AstNode qyInput)

Answer 1

选择应用了命名空间的节点时，您的 XPath 表达式应包含命名空间。 [参考]

所以 XPath 表达式应该是以下

//fed:TargetScope/EndpointReference/Address

而不是

//TargetScope/EndpointReference/Address

Answer 2

也许这有帮助...尝试下面的代码：

foreach (XmlNode targetScopeNode in fedMetaDocument.GetElementsByTagName("Address"))
{
  targetScopeNode.InnerText = tsakListUrl;
}

Answer 3

此外，

mgr.AddNamespace("fed", "http://docs.oasis-open.org/wsfed/federation/200706");

您还需要为默认名称空间声明一个前缀：

mgr.AddNamespace("meta", "urn:oasis:names:tc:SAML:2.0:metadata");

然后在该名称空间中的所有元素上使用它：

fedMetaDocument.SelectNodes("fed:TargetScopes/meta:EndpointReference/meta:Address", mgr))

名称空间是那些如果您不了解基础知识的事物之一，如果您不了解基本原理，那么它真的会让您陷入困境你试图通过反复试验让它们工作。请参阅我之前关于默认命名空间和 XPath 的回答。