Validation Using the XmlSchemaSet
The XmlSchemaSet is a cache or library where the XML Schema definition language (XSD) schemas can be stored. XmlSchemaSet improves performance by caching schemas in memory instead of accessing them from a file or a URL. Each schema in the XmlSchemaSet is identified by the namespace URI and schema location specified when then schema was added to the XmlSchemaSet. The Schemas property assigns the XmlSchemaSet object to use.
Example
The following example validates an XML file using schemas stored in the XmlSchemaSet. The namespace in the XML file, urn:bookstore-schema, identifies which schema in the XmlSchemaSet to use for validation.
using System; using System.Xml; using System.Xml.Schema; using System.IO; public class Sample { public static void Main() { // Create the XmlSchemaSet class. XmlSchemaSet sc = new XmlSchemaSet(); // Add the schema to the collection. sc.Add("urn:bookstore-schema", "books.xsd"); // Set the validation settings. XmlReaderSettings settings = new XmlReaderSettings(); settings.ValidationType = ValidationType.Schema; settings.Schemas = sc; settings.ValidationEventHandler += new ValidationEventHandler (ValidationCallBack); // Create the XmlReader object. XmlReader reader = XmlReader.Create("booksSchemaFail.xml", settings); // Parse the file. while (reader.Read()); } // Display any validation errors. private static void ValidationCallBack(object sender, ValidationEventArgs e) { Console.WriteLine("Validation Error: {0}", e.Message); } }
#using <mscorlib.dll>
#using <System.Xml.dll>
using namespace System;
using namespace System::Xml;
using namespace System::Xml::Schema;
using namespace System::IO;
// Display any validation errors.
static void ValidationCallBack(Object* /*sender*/, ValidationEventArgs* e) {
Console::WriteLine(S"Validation Error: {0}", e->Message);
}
int main() {
// Create the XmlSchemaSet class.
XmlSchemaSet* sc = new XmlSchemaSet();
// Add the schema to the collection.
sc->Add(S"urn:bookstore-schema", S"books.xsd");
// Set the validation settings.
XmlReaderSettings* settings = new XmlReaderSettings();
settings->XsdValidate = true;
settings->Schemas = sc;
settings->ValidationEventHandler += new ValidationEventHandler (ValidationCallBack);
// Create the XmlReader object.
XmlReader* reader = XmlReader::Create(S"booksSchemaFail.xml", settings);
// Parse the file.
while (reader->Read());
return 1;
}
Input
The sample uses the following two input files.
booksSchemaFail.xml
<?xml version='1.0'?>
<bookstore xmlns="urn:bookstore-schema">
<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>
<book genre="philosophy">
<title>The Gorgias</title>
<author>
<name>Plato</name>
</author>
<price>9.99</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>
Output
Validation Error: The element 'book' in namespace 'urn:bookstore-schema' has invalid child element 'author' in namespace 'urn:bookstore-schema'. Expected 'title' in namespace 'urn:bookstore-schema'.
Validation Error: The element 'author' in namespace 'urn:bookstore-schema' has invalid child element 'name' in namespace 'urn:bookstore-schema'. Expected 'first-name' in namespace 'urn:bookstore-schema'.
See Also
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