XmlSchemaSet.ValidationEventHandler Event

Definition

Namespace:

System.Xml.Schema

Assembly:

System.Xml.ReaderWriter.dll

Source:

XmlSchemaSet.cs

Specifies an event handler for receiving information about XML Schema definition language (XSD) schema validation errors.

public:
 event System::Xml::Schema::ValidationEventHandler ^ ValidationEventHandler;

public event System.Xml.Schema.ValidationEventHandler ValidationEventHandler;

member this.ValidationEventHandler : System.Xml.Schema.ValidationEventHandler 

Event Type

ValidationEventHandler

Examples

The following code example illustrates adding a ValidationEventHandler to capture errors and warnings when validating an XML document against a schema.

#using <System.Xml.dll>

using namespace System;
using namespace System::Xml;
using namespace System::Xml::Schema;

static void booksSettingsValidationEventHandler( Object^ /*sender*/, ValidationEventArgs^ e )
{
   if ( e->Severity == XmlSeverityType::Warning )
   {
      Console::Write( L"WARNING: " );
      Console::WriteLine( e->Message );
   }
   else
   if ( e->Severity == XmlSeverityType::Error )
   {
      Console::Write( L"ERROR: " );
      Console::WriteLine( e->Message );
   }
}

int main()
{
   XmlReaderSettings^ booksSettings = gcnew XmlReaderSettings;
   booksSettings->Schemas->Add( L"http://www.contoso.com/books", L"books.xsd" );
   booksSettings->ValidationType = ValidationType::Schema;
   booksSettings->ValidationEventHandler += gcnew ValidationEventHandler( booksSettingsValidationEventHandler );
   XmlReader^ books = XmlReader::Create( L"books.xml", booksSettings );
   while ( books->Read() )
   {}

   return 0;
}

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

class XmlSchemaSetExample
{
    static void Main()
    {
        XmlReaderSettings booksSettings = new XmlReaderSettings();
        booksSettings.Schemas.Add("http://www.contoso.com/books", "books.xsd");
        booksSettings.ValidationType = ValidationType.Schema;
        booksSettings.ValidationEventHandler += new ValidationEventHandler(booksSettingsValidationEventHandler);

        XmlReader books = XmlReader.Create("books.xml", booksSettings);

        while (books.Read()) { }
    }

    static void booksSettingsValidationEventHandler(object sender, ValidationEventArgs e)
    {
        if (e.Severity == XmlSeverityType.Warning)
        {
            Console.Write("WARNING: ");
            Console.WriteLine(e.Message);
        }
        else if (e.Severity == XmlSeverityType.Error)
        {
            Console.Write("ERROR: ");
            Console.WriteLine(e.Message);
        }
    }
}

Imports System.Xml
Imports System.Xml.Schema

Class XmlSchemaSetExample

    Shared Sub Main()

        Dim booksSettings As XmlReaderSettings = New XmlReaderSettings()
        booksSettings.Schemas.Add("http://www.contoso.com/books", "books.xsd")
        booksSettings.ValidationType = ValidationType.Schema
        AddHandler booksSettings.ValidationEventHandler, New ValidationEventHandler(AddressOf booksSettingsValidationEventHandler)

        Dim books As XmlReader = XmlReader.Create("books.xml", booksSettings)

        While books.Read()

        End While

    End Sub

    Shared Sub booksSettingsValidationEventHandler(ByVal sender As Object, ByVal e As ValidationEventArgs)

        If e.Severity = XmlSeverityType.Warning Then
            Console.Write("WARNING: ")
            Console.WriteLine(e.Message)

        ElseIf e.Severity = XmlSeverityType.Error Then
            Console.Write("ERROR: ")
            Console.WriteLine(e.Message)
        End If

    End Sub

End Class

The example uses the books.xml file as an input.

<bookstore xmlns="http://www.contoso.com/books">
  <book genre="autobiography" publicationdate="1981" 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" 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" ISBN="1-861001-57-6">
    <title>The Gorgias</title>
    <author>
      <name>Plato</name>
    </author>
    <price>9.99</price>
  </book>
</bookstore>

The example uses the books.xsd file as an input.

<?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:unsignedShort" use="required" />
                        <xs:attribute name="ISBN" type="xs:string" use="required" />
                    </xs:complexType>
                </xs:element>
            </xs:sequence>
        </xs:complexType>
    </xs:element>
</xs:schema>

Remarks

Sets an event handler for receiving information about schema validation errors when the Add or Compile methods of the XmlSchemaSet are called.

If an event handler is not defined, an XmlSchemaException is thrown on any validation errors where the XmlSeverityType is Error. Exceptions are not thrown for validation errors with an XmlSeverityType of Warning.