XmlValidatingReader.ValidationEventHandler Evento

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

public event System.Xml.Schema.ValidationEventHandler ValidationEventHandler;

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

Tipo de evento

ValidationEventHandler

Exemplos

O exemplo a seguir valida um arquivo em um esquema XML.

#using <System.Xml.dll>

using namespace System;
using namespace System::IO;
using namespace System::Xml;
using namespace System::Xml::Schema;
public ref class Sample
{
private:
   XmlTextReader^ txtreader;
   XmlValidatingReader^ reader;
   Boolean m_success;

public:
   Sample()
   {
      txtreader = nullptr;
      reader = nullptr;
      m_success = true;
      
      //Validate file against the XSD schema. 
      //The validation should fail.
      Validate( "notValidXSD.xml" );
   }


private:
   void Validate( String^ filename )
   {
      try
      {
         Console::WriteLine( "Validating XML file {0}", filename );
         txtreader = gcnew XmlTextReader( filename );
         reader = gcnew XmlValidatingReader( txtreader );
         
         // Set the validation event handler
         reader->ValidationEventHandler += gcnew ValidationEventHandler( this, &Sample::ValidationEventHandle );
         
         // Read XML data
         while ( reader->Read() )
         {}
         Console::WriteLine( "Validation finished. Validation {0}", (m_success == true ? (String^)"successful" : "failed") );
      }
      finally
      {
         
         //Close the reader.
         if ( reader != nullptr )
                  reader->Close();
      }

   }


   //Display the validation error.
   void ValidationEventHandle( Object^ /*sender*/, ValidationEventArgs^ args )
   {
      m_success = false;
      Console::WriteLine( "\r\n\tValidation error: {0}", args->Message );
   }

};

int main()
{
   gcnew Sample;
}

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

public class Sample
{

  private XmlTextReader txtreader = null;
  private XmlValidatingReader reader = null;
  private Boolean m_success = true;

  public Sample ()
  {
        //Validate file against the XSD schema.
        //The validation should fail.
        Validate("notValidXSD.xml");
  }

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

  private void Validate(String filename)
  {
     try
     {
        Console.WriteLine("Validating XML file " + filename.ToString());
        txtreader = new XmlTextReader (filename);
        reader = new XmlValidatingReader (txtreader);

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

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

     finally
     {
        //Close the reader.
        if (reader != null)
          reader.Close();
     }
  }

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

Imports System.IO
Imports System.Xml
Imports System.Xml.Schema

Public Class Sample
    
    Private txtreader As XmlTextReader = Nothing
    Private reader As XmlValidatingReader = Nothing
    Private m_success As Boolean = True
    
    Public Sub New()
        'Validate file against the XSD schema. 
        'The validation should fail.
        Validate("notValidXSD.xml")
    End Sub
    
    Public Shared Sub Main()
        Dim validation As New Sample()
    End Sub
    
    Private Sub Validate(filename As String)
        Try
            Console.WriteLine("Validating XML file " & filename.ToString())
            txtreader = New XmlTextReader(filename)
            reader = New XmlValidatingReader(txtreader)
            
            ' Set the validation event handler
            AddHandler reader.ValidationEventHandler, AddressOf Me.ValidationEventHandle
            
            ' Read XML data
            While reader.Read()
            End While
            Console.WriteLine("Validation finished. Validation {0}", IIf(m_success, "successful", "failed"))
        
        Finally
            'Close the reader.
            If Not (reader Is Nothing) Then
                reader.Close()
            End If
        End Try
    End Sub
     
    'Display the validation error.
    Private Sub ValidationEventHandle(sender As Object, args As ValidationEventArgs)
        m_success = False
        Console.WriteLine(ControlChars.CrLf & ControlChars.Tab & "Validation error: " & args.Message)
    End Sub
End Class

O exemplo usa os dois arquivos de entrada a seguir:

notValidXSD.xml (O xsi:schemaLocation atributo identifica o esquema XML para o leitor.)

<?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>

Comentários

Esses eventos ocorrem durante Read e somente se um ValidationType DTD, XDR, Esquema ou Auto for especificado.

Se nenhum manipulador de eventos for fornecido, um XmlException será gerado no primeiro erro de validação (Severidade é igual a XmlSeverityType.Error).

O manipulador de retorno de chamada pode usar a ValidationEventArgs.Severity propriedade para garantir que um documento de instância XML seja validado em relação a um esquema. A Severity propriedade permite distinguir entre erros de validação (Severidade é igual a XmlSeverityType.Error) que indicam um erro fatal e avisos de validação (Severidade é igual a XmlSeverityType.Warning) que indicam que nenhuma informação de esquema está disponível.

Aplica-se a

Confira também

• XmlSeverityType
• XmlReader