Validation
Validation is the process of comparing an XML document to a corresponding schema. If an XML document conforms to all of the rules in the schema, the document is considered valid. As an introduction to validation, this section provides the following topics:
See Also
IXMLDOMSchemaCollection/XMLSchemaCache
Other Resources 
World Wide Web Consortium (W3C) XML Schema Part 2: Datatypes | World Wide Web Consortium (W3C) XML Schema Part 1: Structures