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Validating XML Data with XmlReader
To define the structure of an XML document, as well as its element relationships, data types, and content constraints, you use a document type definition (DTD) or schema. Although an XML document is considered to be well formed if it meets all the syntactical requirements defined by the World Wide Web Consortium (W3C) Extensible Markup Language (XML) 1.0 Recommendation, it is not considered valid unless it is well formed and also conforms to the constraints defined by its DTD or schema. Therefore, although all valid XML documents are well formed, not all well-formed XML documents are valid.
For more information about XML, see the W3C XML 1.0 Recommendation. For more information about XML Schema, see the W3C XML Schema Part 1: Structures Recommendation and the W3C XML Schema Part 2: Datatypes Recommendation.
The XmlReader class can enforce validation using a DTD or Schema definition language (XSD) schema. The ValidationType property on the XmlReaderSettings class determine whether the XmlReader instance enforces validation.