The XML API for the .NET Framework comprises the following set of functionalities:

XML readers: With XML readers the client application get reference to instance of reader class. Reader class allows you to scroll forward through the contents like moving from node to node or element to element. You can compare it with the "SqlDataReader" object in ADO.NET which is forward only. In short XML reader allows you to browse through the XML document.

XML writers Using XML writers you can store the XML contents to any other storage media. For instance you want to store the whole in memory XML to a physical file or any other media.

XML document classes XML documents provides a in memory representation for the data in an XMLDOM structure as defined by W3C. It also supports browsing and editing of the document. So it gives you a complete memory tree structure representation of your XML document.