XmlDocument.Validate Method (ValidationEventHandler)

Validates the XmlDocument against the XML Schema Definition Language (XSD) schemas contained in the Schemas property.

Namespace:  System.Xml
Assembly:  System.Xml (in System.Xml.dll)

public void Validate(
	ValidationEventHandler validationEventHandler
)

Parameters

validationEventHandler
Type: System.Xml.Schema.ValidationEventHandler

The ValidationEventHandler object that receives information about schema validation warnings and errors.

ExceptionCondition
XmlSchemaValidationException

A schema validation event occurred and no ValidationEventHandler object was specified.

The Validate method validates the XML data in the XmlDocument against the schemas contained in the Schemas property. The Validate method performs infoset augmentation. Specifically, after successful validation, schema defaults are applied, text values are converted to atomic values as necessary, and type information is associated with validated information items. The result is a previously un-typed XML sub-tree in the XmlDocument replaced with a typed sub-tree.

The following are important notes to consider when using the Validate method.

  • Schema location hints like xsi:schemaLocation or xsi:noNamespaceSchemaLocation are ignored.

  • Inline schemas are ignored.

  • If schema validation errors occur during validation the XmlDocument becomes partially validated with some nodes with correct type information and some without.

  • The validation process includes checking for uniqueness and reference constraints (xs:ID, xs:IDREF, xs:key, xs:keyref, and xs:unique).

The following example illustrates use of the Validate method. The example creates an XmlDocument that contains an associated XSD schema using the XmlReaderSettings and XmlReader objects. The example then uses the XPathNavigator class to incorrectly modify the typed value of an element in the XML document generating a schema validation error.

using System;
using System.Xml;
using System.Xml.Schema;
using System.Xml.XPath;

class XPathValidation
{
    static void Main()
    {
        try
        {
            XmlReaderSettings settings = new XmlReaderSettings();
            settings.Schemas.Add("http://www.contoso.com/books", "contosoBooks.xsd");
            settings.ValidationType = ValidationType.Schema;

            XmlReader reader = XmlReader.Create("contosoBooks.xml", settings);
            XmlDocument document = new XmlDocument();
            document.Load(reader);

            ValidationEventHandler eventHandler = new ValidationEventHandler(ValidationEventHandler);

            // the following call to Validate succeeds.
            document.Validate(eventHandler);

            // add a node so that the document is no longer valid
            XPathNavigator navigator = document.CreateNavigator();
            navigator.MoveToFollowing("price", "http://www.contoso.com/books");
            XmlWriter writer = navigator.InsertAfter();
            writer.WriteStartElement("anotherNode", "http://www.contoso.com/books");
            writer.WriteEndElement();
            writer.Close();

            // the document will now fail to successfully validate
            document.Validate(eventHandler);
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }
    }

    static void ValidationEventHandler(object sender, ValidationEventArgs e)
    {
        switch (e.Severity)
        {
            case XmlSeverityType.Error:
                Console.WriteLine("Error: {0}", e.Message);
                break;
            case XmlSeverityType.Warning:
                Console.WriteLine("Warning {0}", e.Message);
                break;
        }

    }
}

The example takes the contosoBooks.xml and contosoBooks.xsd files as input.

<bookstore xmlns="http://www.contoso.com/books">
    <book genre="autobiography" publicationdate="1981-03-22" ISBN="1-861003-11-0">
        <title>The Autobiography of Benjamin Franklin</title>
        <author>
            <first-name>Benjamin</first-name>
            <last-name>Franklin</last-name>
        </author>
        <price>8.99</price>
    </book>
    <book genre="novel" publicationdate="1967-11-17" ISBN="0-201-63361-2">
        <title>The Confidence Man</title>
        <author>
            <first-name>Herman</first-name>
            <last-name>Melville</last-name>
        </author>
        <price>11.99</price>
    </book>
    <book genre="philosophy" publicationdate="1991-02-15" ISBN="1-861001-57-6">
        <title>The Gorgias</title>
        <author>
            <name>Plato</name>
        </author>
        <price>9.99</price>
    </book>
</bookstore>
<?xml version="1.0" encoding="utf-8"?>
<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.contoso.com/books" xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:element name="bookstore">
        <xs:complexType>
            <xs:sequence>
                <xs:element maxOccurs="unbounded" name="book">
                    <xs:complexType>
                        <xs:sequence>
                            <xs:element name="title" type="xs:string" />
                            <xs:element name="author">
                                <xs:complexType>
                                    <xs:sequence>
                                        <xs:element minOccurs="0" name="name" type="xs:string" />
                                        <xs:element minOccurs="0" name="first-name" type="xs:string" />
                                        <xs:element minOccurs="0" name="last-name" type="xs:string" />
                                    </xs:sequence>
                                </xs:complexType>
                            </xs:element>
                            <xs:element name="price" type="xs:decimal" />
                        </xs:sequence>
                        <xs:attribute name="genre" type="xs:string" use="required" />
                        <xs:attribute name="publicationdate" type="xs:date" use="required" />
                        <xs:attribute name="ISBN" type="xs:string" use="required" />
                    </xs:complexType>
                </xs:element>
            </xs:sequence>
        </xs:complexType>
    </xs:element>
</xs:schema>

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0

.NET Compact Framework

Supported in: 3.5, 2.0

XNA Framework

Supported in: 3.0, 2.0, 1.0
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