.NET & XML

What Is the DOM?

The DOM is an interface for manipulating XML content, structure, and style in an object-oriented fashion. It provides a standardized way of manipulating XML documents, including accessing elements and other nodes, taking actions on an object tree based on events, applying styles to documents, loading documents into object trees and saving object trees to documents, and more.

The DOM is language- and platform-neutral, meaning that it can be applied to any programming language on any hardware platform or operating system. Since its start in 1997, the DOM Working Group has made it a specific goal to ensure the DOM’s language- and platform-neutrality. They’ve been successful; you can easily find a DOM implementation in just about any modern programming language, on any modern hardware platform.

The DOM represents an XML document as a tree of objects. Each object in the tree is called a node. The types of nodes that the DOM specifies are Document, DocumentFragment, DocumentType, EntityReference, Element, Attr, ProcessingInstruction, Comment, Text, CDATASection, Entity, and Notation. Some of these node types can have subnodes, and the types of subnodes that a particular node type can have are specified. To handle collections of nodes, the DOM also specifies a NodeList object and, for dictionaries of nodes (keyed by their names), the NamedNodeMap object. Figure 5-1 shows the DOM inheritance hierarchy.

Figure 5-1. The DOM inheritance hierarchy

The DOM specifies ...