Type: System.Xml.XmlValidatingReader

System.Xml.XmlValidatingReader Class

Assembly: System.Xml.dll
Namespace: System.Xml

Summary: Represents a reader that provides DTD, XML-Data Reduced (XDR) schema, and XML Schema definition language (XSD) schema validation.

C# Syntax:


        public class XmlValidatingReader : XmlReader, IXmlLineInfo

Remarks

XmlValidatingReader implements the XmlReader class and provides support for data validation. Use the XmlValidatingReader.Schemas property to have the reader validate using schema files cached in an XmlSchemaCollection. The XmlValidatingReader.ValidationType property specifies what type of validation the reader should perform. Setting the property to ValidationType.None creates a non-validating reader.

If you do not need data validation, the ability to resolve general entities, or support for default attributes, use XmlTextReader.

To read XML data from an XmlNode, use XmlNodeReader.

See also:

System.Xml Namespace

System.Xml.XmlValidatingReader Member List:

Public Constructors

ctor #1	Overloaded: `.ctor(XmlReader reader)` Initializes a new instance of the XmlValidatingReader class that validates the content returned from the given XmlReader.
ctor #2	Overloaded: `.ctor(Stream xmlFragment, XmlNodeType fragType, XmlParserContext context)` Initializes a new instance of the XmlValidatingReader class with the specified values.
ctor #3	Overloaded: `.ctor(string xmlFragment, XmlNodeType fragType, XmlParserContext context)` Initializes a new instance of the XmlValidatingReader class with the specified values.

Public Properties

AttributeCount	Read-only Overridden: Gets the number of attributes on the current node.
BaseURI	Read-only Overridden: Gets the base URI of the current node.
CanResolveEntity	Read-only Overridden: Gets a value indicating whether this reader can parse and resolve entities.
Depth	Read-only Overridden: Gets the depth of the current node in the XML document.
Encoding	Read-only Gets the encoding attribute for the document.
EntityHandling	Read-write Gets or sets a value that specifies how the reader handles entities.
EOF	Read-only Overridden: Gets a value indicating whether the reader is positioned at the end of the stream.
HasAttributes (inherited from System.Xml.XmlReader)	Read-only See base class member description: System.Xml.XmlReader.HasAttributes Gets a value indicating whether the current node has any attributes.
HasValue	Read-only Overridden: Gets a value indicating whether the current node can have a XmlValidatingReader.Value.
IsDefault	Read-only Overridden: Gets a value indicating whether the current node is an attribute that was generated from the default value defined in the DTD or schema.
IsEmptyElement	Read-only Overridden: Gets a value indicating whether the current node is an empty element (for example, `<MyElement/>`).
Item	Read-only Overloaded: `Item[int i] {get`Overridden: Gets the value of the attribute with the specified index.
Item	Read-only Overloaded: `Item[string name] {get`Overridden: Gets the value of the attribute with the specified name.
Item	Read-only Overloaded: `Item[string name, string namespaceURI] {get`Overridden: Gets the value of the attribute with the specified local name and namespace URI.
LocalName	Read-only Overridden: Gets the local name of the current node.
Name	Read-only Overridden: Gets the qualified name of the current node.
Namespaces	Read-write Gets or sets a value indicating whether to do namespace support.
NamespaceURI	Read-only Overridden: Gets the namespace URI (as defined in the W3C Namespace specification) of the node on which the reader is positioned.
NameTable	Read-only Overridden: Gets the XmlNameTable associated with this implementation.
NodeType	Read-only Overridden: Gets the type of the current node.
Prefix	Read-only Overridden: Gets the namespace prefix associated with the current node.
QuoteChar	Read-only Overridden: Gets the quotation mark character used to enclose the value of an attribute node.
Reader	Read-only Gets the XmlReader used to construct this XmlValidatingReader.
ReadState	Read-only Overridden: Gets the state of the reader.
Schemas	Read-only Gets a XmlSchemaCollection to use for validation.
SchemaType	Read-only Gets a schema type object.
ValidationType	Read-write Gets a value describing what type of validation to perform.
Value	Read-only Overridden: Gets the text value of the current node.
XmlLang	Read-only Overridden: Gets the current xml:lang scope.
XmlResolver	Write-only Sets the XmlResolver used for resolving external DTD and schema location references. The XmlResolver is also used to handle any import or include elements found in XML Schema definition language (XSD) schemas.
XmlSpace	Read-only Overridden: Gets the current xml:space scope.

Public Methods

Close	Overridden: Changes the XmlReader.ReadState to Closed.
Equals (inherited from System.Object)	See base class member description: System.Object.Equals Derived from System.Object, the primary base class for all objects.
GetAttribute	Overloaded: `GetAttribute(int i)`Overridden: Gets the value of the attribute with the specified index.
GetAttribute	Overloaded: `GetAttribute(string name)`Overridden: Gets the value of the attribute with the specified name.
GetAttribute	Overloaded: `GetAttribute(string localName, string namespaceURI)`Overridden: Gets the value of the attribute with the specified local name and namespace URI.
GetHashCode (inherited from System.Object)	See base class member description: System.Object.GetHashCode Derived from System.Object, the primary base class for all objects.
GetType (inherited from System.Object)	See base class member description: System.Object.GetType Derived from System.Object, the primary base class for all objects.
IsStartElement (inherited from System.Xml.XmlReader)	Overloaded: `IsStartElement()`See base class member description: System.Xml.XmlReader.IsStartElement Calls XmlReader.MoveToContent and tests if the current content node is a start tag or empty element tag.
IsStartElement (inherited from System.Xml.XmlReader)	Overloaded: `IsStartElement(string name)`See base class member description: System.Xml.XmlReader.IsStartElement Calls XmlReader.MoveToContent and tests if the current content node is a start tag or empty element tag and if the XmlReader.Name property of the element found matches the given argument.
IsStartElement (inherited from System.Xml.XmlReader)	Overloaded: `IsStartElement(string localname, string ns)`See base class member description: System.Xml.XmlReader.IsStartElement Calls XmlReader.MoveToContent and tests if the current content node is a start tag or empty element tag and if the XmlReader.LocalName and XmlReader.NamespaceURI properties of the element found match the given strings.
LookupNamespace	Overridden: Resolves a namespace prefix in the current element's scope.
MoveToAttribute	Overloaded: `MoveToAttribute(int i)`Overridden: Moves to the attribute with the specified index.
MoveToAttribute	Overloaded: `MoveToAttribute(string name)`Overridden: Moves to the attribute with the specified name.
MoveToAttribute	Overloaded: `MoveToAttribute(string localName, string namespaceURI)`Overridden: Moves to the attribute with the specified local name and namespace URI.
MoveToContent (inherited from System.Xml.XmlReader)	See base class member description: System.Xml.XmlReader.MoveToContent Checks whether the current node is a content (non-white space text, CDATA, Element, EndElement, EntityReference, or EndEntity) node. If the node is not a content node, the reader skips ahead to the next content node or end of file. It skips over nodes of the following type: ProcessingInstruction, DocumentType, Comment, Whitespace, or SignificantWhitespace.
MoveToElement	Overridden: Moves to the element that contains the current attribute node.
MoveToFirstAttribute	Overridden: Moves to the first attribute.
MoveToNextAttribute	Overridden: Moves to the next attribute.
Read	Overridden: Reads the next node from the stream.
ReadAttributeValue	Overridden: Parses the attribute value into one or more Text, EntityReference, or EndEntity nodes.
ReadElementString (inherited from System.Xml.XmlReader)	Overloaded: `ReadElementString()`See base class member description: System.Xml.XmlReader.ReadElementString Reads a text-only element.
ReadElementString (inherited from System.Xml.XmlReader)	Overloaded: `ReadElementString(string name)`See base class member description: System.Xml.XmlReader.ReadElementString Checks that the XmlReader.Name property of the element found matches the given string before reading a text-only element.
ReadElementString (inherited from System.Xml.XmlReader)	Overloaded: `ReadElementString(string localname, string ns)`See base class member description: System.Xml.XmlReader.ReadElementString Checks that the XmlReader.LocalName and XmlReader.NamespaceURI properties of the element found matches the given strings before reading a text-only element.
ReadEndElement (inherited from System.Xml.XmlReader)	See base class member description: System.Xml.XmlReader.ReadEndElement Checks that the current content node is an end tag and advances the reader to the next node.
ReadInnerXml	Overridden: Reads all the content, including markup, as a string.
ReadOuterXml	Overridden: Reads the content, including markup, representing this node and all its children.
ReadStartElement (inherited from System.Xml.XmlReader)	Overloaded: `ReadStartElement()`See base class member description: System.Xml.XmlReader.ReadStartElement Checks that the current node is an element and advances the reader to the next node.
ReadStartElement (inherited from System.Xml.XmlReader)	Overloaded: `ReadStartElement(string name)`See base class member description: System.Xml.XmlReader.ReadStartElement Checks that the current content node is an element with the given XmlReader.Name and advances the reader to the next node.
ReadStartElement (inherited from System.Xml.XmlReader)	Overloaded: `ReadStartElement(string localname, string ns)`See base class member description: System.Xml.XmlReader.ReadStartElement Checks that the current content node is an element with the given XmlReader.LocalName and XmlReader.NamespaceURI and advances the reader to the next node.
ReadString	Overridden: Reads the contents of an element or text node as a string.
ReadTypedValue	Gets the common language runtime type for the specified XML Schema definition language (XSD) type.
ResolveEntity	Overridden: Resolves the entity reference for EntityReference nodes.
Skip (inherited from System.Xml.XmlReader)	See base class member description: System.Xml.XmlReader.Skip Skips the children of the current node.
ToString (inherited from System.Object)	See base class member description: System.Object.ToString Derived from System.Object, the primary base class for all objects.

Public Events

ValidationEventHandler

Sets an event handler for receiving information about DTD, XML-Data Reduced (XDR) schema, and XML Schema definition language (XSD) schema validation errors.

Protected Methods

Finalize (inherited from System.Object)	See base class member description: System.Object.Finalize Derived from System.Object, the primary base class for all objects.
MemberwiseClone (inherited from System.Object)	See base class member description: System.Object.MemberwiseClone Derived from System.Object, the primary base class for all objects.

Hierarchy:

System.Object

System.Xml.XmlReader

System.Xml.XmlValidatingReader

System.Xml.XmlValidatingReader Member Details

Overloaded ctor #1

Summary: Initializes a new instance of the XmlValidatingReader class that validates the content returned from the given XmlReader.

C# Syntax:


            public XmlValidatingReader(
   XmlReader reader
);

Parameters:

reader

The XmlReader to read from while validating. The current implementation only supports XmlTextReader.

Exceptions

Exception Type	Condition
ArgumentException	The reader specified is not an XmlTextReader.

Remarks

All nodes returned from the given XmlReader are also returned from this validating reader, so there is no information loss in the process. New nodes not returned from the underlying reader may be added by this reader (for example, default attributes and the children of an entity reference). Any properties set on the given XmlTextReader also applies to this validating reader. For example, if the supplied reader had WhitespaceHandling.None set, this validating reader also ignores whitespace.

When external DTDs or schemas are needed for validation the XmlValidatingReader.XmlResolver property sets the XmlResolver object to use for resolving external resources.

Example

The following example validates two documents.

using System;
using System.IO;
using System.Xml;
using System.Xml.Schema;

public class Sample
{

  private Boolean m_success = true;

  public Sample ()
  {
      //Validate the document using an external XSD schema.  Validation should fail.
      Validate("notValidXSD.xml"); 

      //Validate the document using an inline XSD. Validation should succeed.
      Validate("inlineXSD.xml");
  }    

  public static void Main ()
  {
      Sample validation = new Sample();
  }

  private void Validate(String filename)
  {    
      m_success = true;
      Console.WriteLine("\r\n******");
      Console.WriteLine("Validating XML file " + filename.ToString());
      XmlTextReader txtreader = new XmlTextReader (filename);
      XmlValidatingReader reader = new XmlValidatingReader (txtreader);

      // Set the validation event handler
      reader.ValidationEventHandler += new ValidationEventHandler (ValidationCallBack);

      // Read XML data
      while (reader.Read()){}
      Console.WriteLine ("Validation finished. Validation {0}", (m_success==true ? "successful!" : "failed."));

      //Close the reader.
      reader.Close();
  }

  //Display the validation error.
  public void ValidationCallBack (object sender, ValidationEventArgs args)
  {
     m_success = false;
     Console.WriteLine("\r\n\tValidation error: " + args.Message );
  }
}

The sample uses the following input files:

notValidXSD.xml

<?xml version='1.0'?>
<bookstore xmlns="urn:bookstore-schema"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="urn:bookstore-schema books.xsd">
  <book>
    <author>
      <first-name>Benjamin</first-name>
      <last-name>Franklin</last-name>
    </author>
  </book>
  <book genre="novel">
    <title>The Confidence Man</title>
    <author>
      <first-name>Herman</first-name>
      <last-name>Melville</last-name>
    </author>
    <price>11.99</price>
  </book>
</bookstore>

books.xsd

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    xmlns="urn:bookstore-schema"
    elementFormDefault="qualified"
    targetNamespace="urn:bookstore-schema">

 <xsd:element name="bookstore" type="bookstoreType"/>

 <xsd:complexType name="bookstoreType">
  <xsd:sequence maxOccurs="unbounded">
   <xsd:element name="book"  type="bookType"/>
  </xsd:sequence>
 </xsd:complexType>

 <xsd:complexType name="bookType">
  <xsd:sequence>
   <xsd:element name="title" type="xsd:string"/>
   <xsd:element name="author" type="authorName"/>
   <xsd:element name="price"  type="xsd:decimal"/>
  </xsd:sequence>
  <xsd:attribute name="genre" type="xsd:string"/>
 </xsd:complexType>

 <xsd:complexType name="authorName">
  <xsd:sequence>
   <xsd:element name="first-name"  type="xsd:string"/>
   <xsd:element name="last-name" type="xsd:string"/>
  </xsd:sequence>
 </xsd:complexType>

</xsd:schema>

inlineXSD.xml

<store-data>
<!--Inline XSD schema-->
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
 <xsd:element name="bookstore" type="bookstoreType"/>
 <xsd:complexType name="bookstoreType">
  <xsd:sequence maxOccurs="unbounded">
   <xsd:element name="book"  type="bookType"/>
  </xsd:sequence>
 </xsd:complexType>

 <xsd:complexType name="bookType">
  <xsd:sequence>
   <xsd:element name="title" type="xsd:string"/>
   <xsd:element name="price"  type="xsd:decimal"/>
  </xsd:sequence>
  <xsd:attribute name="genre" type="xsd:string"/>
 </xsd:complexType>
</xsd:schema>
<!-- end of schema -->

<bookstore>
  <book genre="novel">
    <title>Pride And Prejudice</title>
    <price>19.95</price>
  </book>
</bookstore>
</store-data>

See also:
XmlTextReader

XmlNodeType	Fragment May Contain
Element	Any valid element content (for example, any combination of elements, comments, processing instructions, cdata, text, entity references).
Attribute	The value of an attribute (the part inside the quotes).
Document	The contents of an entire XML document; this enforces document level rules.

Node Type	Value
Attribute	The value of the attribute.
CDATA	The content of the CDATA section.
Comment	The content of the comment.
DocumentType	The internal subset.
ProcessingInstruction	The entire content, excluding the target.
SignificantWhitespace	The whitespace between markup in a mixed content model.
Text	The content of the text node.
Whitespace	The whitespace between markup.
XmlDeclaration	The content of the declaration.

Node Type	Child Content	Return Value	Position After the Call
Element	<item>text</item>	text	After the end tag.
Attribute	<item attr1="val1" attr2="val2">text</item>	val1	Remains on the attribute node attr1 .

Value	Description
ExpandEntities	Returns expanded character and general entities. This is the default.
ExpandCharEntities	Returns the text content up to but not including a general entity reference. This means a general entity causes ReadString to stop. You must call Read to step over the entity reference.

Depth	NodeType	Name	Value
1	Text		A
1	EntityReference	num
1	SignificantWhitespace