internal static void GenerateXPath()
{
XDocument aspNetRss = XDocument.Load("https://weblogs.asp.net/dixin/rss");
XElement element1 = aspNetRss
.Root
.Element("channel")
.Elements("item")
.Last();
element1.XPath().WriteLine(); // /rss/channel/item[20]
XElement element2 = aspNetRss.XPathSelectElement(element1.XPath());
object.ReferenceEquals(element1, element2).WriteLine(); // True
XDocument flickrRss = XDocument.Load("https://www.flickr.com/services/feeds/photos_public.gne?id=64715861@N07&format=rss2");
XAttribute attribute1 = flickrRss
.Root
.Descendants("author") // <author flickr:profile="https://www.flickr.com/people/dixin/">...</author>.
.First()
.Attribute(XName.Get("profile", "urn:flickr:user")); // <rss xmlns:flickr="urn:flickr:user">...</rss>.
attribute1.XPath().WriteLine(); // /rss/channel/item[1]/author/@flickr:profile
XAttribute attribute2 = ((IEnumerable <object>)flickrRss
.XPathEvaluate(attribute1.XPath(), flickrRss.CreateNamespaceManager()))
.Cast <XAttribute>()
.Single();
object.ReferenceEquals(attribute1, attribute2).WriteLine(); // True
}
internal static void XPathQueryWithNamespace()
{
XDocument rss = XDocument.Load("https://www.flickr.com/services/feeds/photos_public.gne?id=64715861@N07&format=rss2");
XmlNamespaceManager namespaceManager = rss.CreateNamespaceManager();
IEnumerable <XElement> query1 = rss.XPathSelectElements("/rss/channel/item/media:category", namespaceManager);
query1.Count().WriteLine(); // 20
IEnumerable <XElement> query2 = rss.XPathSelectElements("/rss/channel/item/media:category");
// XPathException: Namespace Manager or XsltContext needed. This query has a prefix, variable, or user-defined function.
}
internal static void XPathEvaluateSequenceWithNamespace()
{
XDocument rss = XDocument.Load("https://www.flickr.com/services/feeds/photos_public.gne?id=64715861@N07&format=rss2");
((IEnumerable <object>)rss
.XPathEvaluate(
"/rss/channel/item[contains(media:category/text(), 'microsoft')]/media:title/text()",
rss.CreateNamespaceManager()))
.Cast <XText>()
.WriteLines(mediaTitle => mediaTitle.Value);
// Chinese President visits Microsoft
// Satya Nadella, CEO of Microsoft
}
public static XmlNamespaceManager CreateNamespaceManager(this XDocument document, Dictionary <string, string> namespaces = null)
{
return(document.CreateNamespaceManager(null, namespaces));
}
