The XML support in ASP.NET provides excellent support for storing, retrieving and rendering XML.
I start with looking at the new web.sitemap file that allows you to store the hierarchy of a Web site and
leverage that to drive the navigation structure of a Web site. Then, I go on to discuss the features of new
XML data controls such as XmlDataSource, TreeView, and GridView for consuming and displaying
native XML directly in the browser. Finally, I also introduce the new ASP.NET 2.0 script callback feature
for retrieving XML data directly from the browser without refreshing the page.
you can learn xml at here