如何使用xDocument和Linq选择元素的孙元素

Question

I have this XML markup:

<preferences>
  <section name="PREF_SECTION_NAME_1">
    <preference name="PREF_EXAMPLE_1" type="text">
      <default value="false"></default>
    </preference>
    <preference name="PREF_EXAMPLE_2" type="radio">
      <default value="true"></default>
    </preference>
    <preference name="PREF_EXAMPLE_3" type="radio">
       <default value="false"></default>
    </preference>
  </section>
  <section name="PREF_SECTION_NAME_2">
    <preference name="PREF_EXAMPLE_4" type="radio">
      <default value="true"></default>
    </preference>
    <preference name="PREF_EXAMPLE_5" type="radio">
      <default value="false"></default>
    </preference>
    <preference name="PREF_EXAMPLE_6" type="radio">
      <default value="true"></default>
    </preference>
  </section>
</preferences>

I want to get the default value for when the Preference attribute name = "PREF_EXAMPLE_2"

I got this:

var t = from p in xDocUser.Descendants("preference").Attributes("name").Where(d=>d.Value==preferencename) select p;

which gives me the Attributes for preference but not its child.

How can i do this please?

Answer 1

Well yes, you're asking for the attributes of preference. It sounds like you actually want something like:

var defaults = from pref in xDocUser.Descendants("preference")
               where (string) pref.Attribute("name") == preferenceName
               select (bool) pref.Element("default").Attribute("value");

That will give you an IEnumerable<bool> of the default values for all the matching preferences.