.NET XML Framework Concepts

Although .NET is a new platform, Microsoft realizes that XML is a fundamentally important technology. So, .NET has been designed to contain extensive XML support right from the beginning. This chapter covers various techniques of working with XML via Microsoft's .NET Interfaces that programmers will need to help them achieve their desired results.

First, programmers need basic methods that allow the data contained within XML Documents to be parsed and accessed programmatically. There are two common approaches to this issue. The lower-level method cycles through the document reporting whenever a node is parsed. There are several standards for this method of parsing, such as the Simple API for XML (SAX). Microsoft has chosen a custom mechanism for this type of parsing and implemented it with its XmlReader interface. With this parsing interface, the parser moves through the document on demand, informing the calling application what has most recently been parsed.

Document based parsing is the other common method for accessing data in an XML Document. The W3C has standardized an interface for this type of access in the Document Object Model (DOM). DOM is discussed in detail in Chapter 14, “XML and the Document Object Model.” Microsoft implements a variant of DOM with its XmlDocument interface.

Second, more advanced methods are required to allow parsed XML to be navigated and transformed. Navigation is accomplished with technologies such as XPath. Transformation is accomplished with implementations of XSLT, which allow the transformation of XML into various other formats such as HTML, PDF, or SVG. Both XPath and XSLT interfaces are included in .NET.

Finally, new more advanced technologies have recently become available that build on this foundation and enable higher level and more complex XML activities to be accomplished. For instance, XML is now being commonly used as a standard protocol for communications between businesses, using specifications such as SOAP and XML-RPC.