Маленький пример LINQ to XML.
XML file
<?xml version="1.0"?>
<catalog>
<book id="bk101">
<author>Gambardella, Matthew</author>
<title>XML Developer's Guide</title>
<genre>Computer</genre>
<price>44.95</price>
<publish_date>2000-10-01</publish_date>
<description>
An in-depth look at creating applications
with XML.
</description>
</book>
<book id="bk102">
<author>Ralls, Kim</author>
<title>Midnight Rain</title>
<genre>Fantasy</genre>
<price>5.95</price>
<publish_date>2000-12-16</publish_date>
<description>
A former architect battles corporate zombies,
an evil sorceress, and her own childhood to become queen
of the world.
</description>
</book>
<book id="bk103">
<author>Corets, Eva</author>
<title>Maeve Ascendant</title>
<genre>Fantasy</genre>
<price>5.95</price>
<publish_date>2000-11-17</publish_date>
<description>
After the collapse of a nanotechnology
society in England, the young survivors lay the
foundation for a new society.
</description>
</book>
</catalog>
LINQ to XML
XElement xElement = XElement.Load("books.xml");
var query = from c in xElement.Descendants("book")
where c.Element("description").Value.Contains("XML")
select c;
foreach (var q in query)
{
Console.WriteLine(q.Element("author").Value + "-" + q.Element("title").Value);
}