C# 混淆我的Xpath表达式应该是什么？

下面给出了我的categories.xml文件

<categories>
  <root name="Cars -Vehicles" id="CV"></root>
  <root name="Personals" id="PER"></root>
  <root name="Real Estate" id="RE"></root>
  <root name="Property For Rent" id="PFR"></root>
  <root name="Community" id="COM"></root>
</categories>

<attributes>

  <attribute value="ethnicity=ethnicity_african_american" name ="American Indian" categoryid="PER"/>
  <attribute value="ethnicity=ethnicity_asian_pacific_islander" name ="Asian - Pacific Islander" categoryid="PER"/>
  <attribute value="ethnicity=ethnicity_caucasian" name ="Caucasian" categoryid="PER"/>


  <attribute value="amenities=amenities_ac" name ="AC" categoryid="RE, PFR"/>
  <attribute value="amenities=amenities_alarm" name ="Alarm" categoryid="RE, PFR"/>

</attributes>

 protected void ddCategories_SelectedIndexChanged(object sender, EventArgs e)
 {
            XmlDataSource xd = new XmlDataSource();
            xd.DataFile = Server.MapPath("Xmls") + "\\attributes.xml";
            xd.XPath = "/attributes/attribute[@categoryid='" + 
                        categoriesDropDown.SelectedValue.ToString() + "']";

            attributeDropdown.DataSource = xd;
            attributeDropdown.DataTextField = "name";
            attributeDropdown.DataValueField = "value";

            attributeDropdown.DataBind();

         // categoriesDropDown.DataTextField = "name";
         // categoriesDropDown.DataValueField = "id";

 }

现在的问题是名为AC和Alarm的两个属性分为两类房地产和出租房地产。如何在选择这些类别时绑定这些属性

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如果属性在多个类别中，我的Xpath表达式应该是什么？

也许这不是一个好的解决方案，但您可以使用

包含
函数，例如：

/attributes/attribute[contains(@categoryid, 'category')]

根据您的代码：

xd.XPath = string.Format("/attributes/attribute[contains(@categoryid, '{0}')]",
    categoriesDropDown.SelectedValue);