如何选择带有XPath的类别XML节点，而不考虑具体的Id？

Question

在C#中，我使用以下代码将XML文件读入到XmlDocument中。在这样做的时候，我试图选择所有的“类别”节点，而不考虑它们使用XPath的特定类别id。我总共有200多个类别，因此逐个选择它们并不是一个真正的选择。

我尝试过无数的"category“、"/category”、"//catalog/category“等变体，但是nodeList总是返回null。我还试着关注下面的网站和其他许多网站。任何帮助或指导都将不胜感激。

w3 schools

XPath Examples - MSDN

var doc = new XmlDocument();
doc.Load(filename);

XmlNodeList nodeList;
XmlNode root = doc.DocumentElement;

nodeList = root.SelectNodes("/catalog/category")



// Sample XML Document 

<?xml version="1.0" encoding="UTF-8"?>
<catalog xmlns="http://www.site.com/catalog/2012-10-31" catalog-id="sports">
    <header>
        <image-settings>
            <internal-location base-path="/"/>
            <view-types>
                <view-type>large</view-type>
                <view-type>small</view-type>
                <view-type>swatch</view-type>
            </view-types>
            <alt-pattern>${productname}</alt-pattern>
            <title-pattern>${productname}</title-pattern>
        </image-settings>
    </header>

    <category category-id="root">
        <display-name xml:lang="x-default">Store Catalog</display-name>
        <description xml:lang="x-default">Holds categories for Store</description>
        <online-flag>true</online-flag>
        <template/>
        <page-attributes>
            <page-title xml:lang="x-default">Store Catalog</page-title>
            <page-description xml:lang="x-default">Welcome to the Store</page-description>
        </page-attributes>
        <custom-attributes>
            <custom-attribute attribute-id="enableCompare">false</custom-attribute>
            <custom-attribute attribute-id="showInMenu">false</custom-attribute>
        </custom-attributes>
        <refinement-definitions>
            <refinement-definition type="category" bucket-type="none">
                <display-name xml:lang="x-default">Category</display-name>
                <sort-mode>category-position</sort-mode>
                <cutoff-threshold>5</cutoff-threshold>
            </refinement-definition>
        </refinement-definitions>
    </category>

    <category category-id="whats-new">
        <display-name xml:lang="x-default">NEW</display-name>
        <online-flag>true</online-flag>
        <parent>root</parent>
        <position>25.0</position>
        <template>rendering/category/categoryproducthits</template>
        <page-attributes>
            <page-title xml:lang="x-default">What's New - New at Store</page-title>
            <page-description xml:lang="x-default">Learn what's new at the store.</page-description>
        </page-attributes>
        <custom-attributes>
            <custom-attribute attribute-id="contentOnly">false</custom-attribute>
            <custom-attribute attribute-id="displaySubNav">false</custom-attribute>
            <custom-attribute attribute-id="dropdownNavSlot1">dropdown-left7</custom-attribute>
            <custom-attribute attribute-id="enableCompare">false</custom-attribute>
            <custom-attribute attribute-id="enableslotat3">true</custom-attribute>
            <custom-attribute attribute-id="enableslotat4">true</custom-attribute>
            <custom-attribute attribute-id="enableslotat9">true</custom-attribute>
            <custom-attribute attribute-id="showInMenu">true</custom-attribute>
            <custom-attribute attribute-id="showShadeSelector">false</custom-attribute>
            <custom-attribute attribute-id="showSubCollectionsAsTabs">false</custom-attribute>
        </custom-attributes>
    </category>

// cut for brevity - the above category nodes are the same format as the rest of the XML document.

Answer 1

由于XML使用显式名称空间，因此似乎必须在SelectNodes方法中指定它：

 XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc.NameTable);
 nsmgr.AddNamespace("cc", "http://www.site.com/catalog/2012-10-31");
 XmlNodeList nodelist = doc.SelectNodes("/cc:catalog/cc:category", nsmgr);