Programming C# 4.0, 6th Edition

Chapter 12. XML

XML (the eXtensible Markup Language) provides an industry-standard method for encoding structured information. It defines syntactic and structural rules that enable software applications to process XML files even when they don’t understand all of the data.

XML specifications are defined and maintained by the World Wide Web Consortium (W3C). The latest version is XML 1.1 (Second Edition). However, XML 1.0 (currently in its fifth edition) is the most popular version, and is supported by all XML parsers. W3C states that:

You are encouraged to create or generate XML 1.0 documents if you do not need the new features in XML 1.1; XML Parsers are expected to understand both XML 1.0 and XML 1.1 (see http://www.w3.org/xml/core/#publications/).

This chapter will introduce XML 1.0 only, and in fact, will focus on just the most commonly used XML features. We’ll introduce you to the XDocument and XElement classes first, and you’ll learn how to create and manipulate XML documents.

Of course, once you have a large document, you’ll want to be able to find substrings, and we’ll show you two different ways to do that, using LINQ. The .NET Framework also allows you to serialize your objects as XML, and deserialize them at their destination. We’ll cover those methods at the end of the chapter.

XML Basics (A Quick Review)

XML is a markup language, not unlike HTML, except that it is extensible—that is, applications that use XML can (and do) create new kinds of elements and attributes.

Elements ...