Question

我有这个文件，我希望获得"x_server_response/retrieve_resources_by_category_response/source_full_info/record/ datafield[@tag='520']/subfield[@code='a']"中的值但我不能！为什么呢？

我怀疑这与记录节点上的命名空间daclaration有关。但我无法弄清楚如何去做。

我的代码如下：

XmlNodeList xmlResources = r.ResponseXmlDocument.SelectNodes("x_server_response/retrieve_resources_by_category_response/source_full_info);              

            foreach (XmlNode xmlResource in xmlResources)   
            {
                string information = xmlResource.SelectSingleNode("record/datafield[@tag='520']/subfield[@code='a']").InnerText;

xml就像这样：

 <x_server_response> metalib_version="4.00 (20)>
    <source_full_info> 
      <record xmlns="http://www.loc.gov/MARC21/slim/" 
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
      xsi:schemaLocation="http://www.loc.gov/MARC21/slim 
      http://www.loc.gov/standards/marcxml/schema/MARC21slim.xsd"> 
      <controlfield tag="001">CKB02166</controlfield> 
                <datafield tag="520" ind1=" " ind2=" "> 
        <subfield code="a">Providing access to thousands of online journals from leading 
        scholarly, academic and business publishers, the Ingenta Select service provides fast and 
        reliable access from a global network of servers to users' desktops around the world. 
        ## ##Ingenta Select provides access to more than 5,000 electronic 
        publications from over 190 publisher clients and bring together an extensive range of services 
        for the librarian and end-user alike</subfield> 
      </datafield>          </record> 
      </source_full_info> 
      <session_id new_session="N">3B7F9EQE259KNK1YUK462VCCG4455T4BUPUC5B9LVQS9XD16U6</session_id>
<x_server_response>

Answer 1

因为部分节点位于"http://www.loc.gov/MARC21/slim/"命名空间中，但您的XPath仅在空命名空间中查找元素。

要解决此问题，请通过调用命名空间管理器使您的环境知道命名空间：

XmlNamespaceManager nsmgr = new XmlNamespaceManager(r.ResponseXmlDocument);
nsmgr.AddNamespace("marc", "http://www.loc.gov/MARC21/slim/");
string xpath = "marc:record/marc:datafield[@tag='520']/marc:subfield[@code='a']";

// ...
string information = xmlResource.SelectSingleNode(xpath).InnerText;

编辑：虽然选择

可能更容易

//marc:datafield[@tag='520']/marc:subfield[@code='a']

并摆脱目前完全采用的两步法。

如何使用choicesinglenode（）访问具有属性和命名空间的xml节点

1 个答案: