.NET & XML

Reading Non-XML Documents with XmlReader

To read any sort of document using a non-XML format as though it were XML, you can extend XmlReader by writing a custom XmlReader subclass. Among the advantages of writing your own XmlReader subclass is that you can use your custom XmlReader wherever you would use any of the built-in XmlReaders. For example, even if the underlying data isn’t formatted using standard XML syntax, you can pass any instance of a custom XmlReader to XmlDocument.Load( ) to load the XML document into a DOM (more on XmlDocument in Chapter 5). You could load a DOM tree from the data, use XPath to query the data, even transform the data with XSLT, all this even though the original data does not look anything like XML.

As long as an alternative syntax provides a hierarchical structure similar to XML, you can create an XmlReader for it that presents its content in a way that looks like XML. In this chapter you’ll learn how to write a custom XmlReader implementation which will enable you to read data formatted in PYX, a line-oriented XML format, as if it were XML.