Processing XML Data In-Memory
The XmlDocument class implements the W3C document object model (DOM) level 1 core and the core DOM level 2 recommendations. The DOM is an in-memory (cache) tree representation of an XML document. With the XmlDocument and its related classes, you can construct XML documents, load and access data, modify data, and save changes.
The XPathDocument class is a read-only, in-memory data store that is based on the XPath data model. The XPathNavigator class offers several editing options and navigation capabilities using a cursor model over XML documents contained in the read-only XPathDocument class as well as the XmlDocument class.
LINQ to XML [from BPUEDev11] is the new model in the .NET Framework version 3.5 for processing XML data. It is an in-memory model that leverages LINQ (Language-Integrated Query). LINQ extends the language syntax of C# and Visual Basic to provide new query capabilities.