XmlSchemaUnique Classe

Definição

Espaço de Nomes:
System.Xml.Schema
Assemblagem:
System.Xml.dll
Assemblagem:
netstandard.dll

Representa o unique elemento do Esquema XML conforme especificado pelo World Wide Web Consortium (W3C). Esta classe pode ser usada para identificar uma restrição única entre um conjunto de elementos.

public ref class XmlSchemaUnique : System::Xml::Schema::XmlSchemaIdentityConstraint
public class XmlSchemaUnique : System.Xml.Schema.XmlSchemaIdentityConstraint
type XmlSchemaUnique = class
    inherit XmlSchemaIdentityConstraint
Public Class XmlSchemaUnique
Inherits XmlSchemaIdentityConstraint
Herança
Object
XmlSchemaObject
XmlSchemaAnnotated
XmlSchemaIdentityConstraint
XmlSchemaUnique

Exemplos

O exemplo seguinte mostra a utilização da XmlSchemaUnique classe.

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

class XMLSchemaExamples
{
    public static void Main()
    {

        XmlSchema schema = new XmlSchema();

        // <xs:complexType name="customerOrderType">
        XmlSchemaComplexType customerOrderType = new XmlSchemaComplexType();
        customerOrderType.Name = "customerOrderType";

        // <xs:sequence>
        XmlSchemaSequence sequence1 = new XmlSchemaSequence();

        // <xs:element name="item" minOccurs="0" maxOccurs="unbounded">
        XmlSchemaElement item = new XmlSchemaElement();
        item.MinOccurs = 0;
        item.MaxOccursString = "unbounded";
        item.Name = "item";

        // <xs:complexType>
        XmlSchemaComplexType ct1 = new XmlSchemaComplexType();

        // <xs:attribute name="itemID" type="xs:string"/>
        XmlSchemaAttribute itemID = new XmlSchemaAttribute();
        itemID.Name = "itemID";
        itemID.SchemaTypeName = new XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema");

        // </xs:complexType>
        ct1.Attributes.Add(itemID);

        // </xs:element>
        item.SchemaType = ct1;

        // </xs:sequence>
        sequence1.Items.Add(item);
        customerOrderType.Particle = sequence1;

        // <xs:attribute name="CustomerID" type="xs:string"/>
        XmlSchemaAttribute CustomerID = new XmlSchemaAttribute();
        CustomerID.Name = "CustomerID";
        CustomerID.SchemaTypeName = new XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema");

        customerOrderType.Attributes.Add(CustomerID);

        // </xs:complexType>
        schema.Items.Add(customerOrderType);

        // <xs:element name="ordersByCustomer">
        XmlSchemaElement ordersByCustomer = new XmlSchemaElement();
        ordersByCustomer.Name = "ordersByCustomer";

        // <xs:complexType>
        XmlSchemaComplexType ct2 = new XmlSchemaComplexType();

        // <xs:sequence>
        XmlSchemaSequence sequence2 = new XmlSchemaSequence();

        // <xs:element name="customerOrders" type="customerOrderType" minOccurs="0" maxOccurs="unbounded" />
        XmlSchemaElement customerOrders = new XmlSchemaElement();
        customerOrders.MinOccurs = 0;
        customerOrders.MaxOccursString = "unbounded";
        customerOrders.Name = "customerOrders";
        customerOrders.SchemaTypeName = new XmlQualifiedName("customerOrderType", "");

        // </xs:sequence>
        sequence2.Items.Add(customerOrders);

        // </xs:complexType>
        ct2.Particle = sequence2;
        ordersByCustomer.SchemaType = ct2;

        // <xs:unique name="oneCustomerOrdersforEachCustomerID">
        XmlSchemaUnique element_unique = new XmlSchemaUnique();
        element_unique.Name = "oneCustomerOrdersforEachCustomerID";

        // <xs:selector xpath="customerOrders"/>
        element_unique.Selector = new XmlSchemaXPath();
        element_unique.Selector.XPath = "customerOrders";

        // <xs:field xpath="@customerID"/>
        XmlSchemaXPath field = new XmlSchemaXPath();
        field.XPath = "@customerID";

        // </xs:unique>
        element_unique.Fields.Add(field);
        ordersByCustomer.Constraints.Add(element_unique);

        // </xs:element>
        schema.Items.Add(ordersByCustomer);

        XmlSchemaSet schemaSet = new XmlSchemaSet();
        schemaSet.ValidationEventHandler += new ValidationEventHandler(ValidationCallbackOne);
        schemaSet.Add(schema);
        schemaSet.Compile();

        XmlSchema compiledSchema = null;

        foreach (XmlSchema schema1 in schemaSet.Schemas())
        {
            compiledSchema = schema1;
        }

        XmlNamespaceManager nsmgr = new XmlNamespaceManager(new NameTable());
        nsmgr.AddNamespace("xs", "http://www.w3.org/2001/XMLSchema");
        compiledSchema.Write(Console.Out, nsmgr);
    }

    public static void ValidationCallbackOne(object sender, ValidationEventArgs args)
    {
        Console.WriteLine(args.Message);
    }
}

Imports System.Xml
Imports System.Xml.Schema

Class XMLSchemaExamples
    Public Shared Sub Main()

        Dim schema As New XmlSchema()

        ' <xs:complexType name="customerOrderType">
        Dim customerOrderType As New XmlSchemaComplexType()
        customerOrderType.Name = "customerOrderType"

        ' <xs:sequence>
        Dim sequence1 As New XmlSchemaSequence()

        ' <xs:element name="item" minOccurs="0" maxOccurs="unbounded">
        Dim item As New XmlSchemaElement()
        item.MinOccurs = 0
        item.MaxOccursString = "unbounded"
        item.Name = "item"

        ' <xs:complexType>
        Dim ct1 As New XmlSchemaComplexType()

        ' <xs:attribute name="itemID" type="xs:string"/>
        Dim itemID As New XmlSchemaAttribute()
        itemID.Name = "itemID"
        itemID.SchemaTypeName = New XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema")

        ' </xs:complexType>
        ct1.Attributes.Add(itemID)

        ' </xs:element>
        item.SchemaType = ct1

        ' </xs:sequence>
        sequence1.Items.Add(item)
        customerOrderType.Particle = sequence1

        ' <xs:attribute name="CustomerID" type="xs:string"/>
        Dim CustomerID As New XmlSchemaAttribute()
        CustomerID.Name = "CustomerID"
        CustomerID.SchemaTypeName = New XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema")

        customerOrderType.Attributes.Add(CustomerID)

        ' </xs:complexType>
        schema.Items.Add(customerOrderType)

        ' <xs:element name="ordersByCustomer">
        Dim ordersByCustomer As New XmlSchemaElement()
        ordersByCustomer.Name = "ordersByCustomer"

        ' <xs:complexType>
        Dim ct2 As New XmlSchemaComplexType()

        ' <xs:sequence>
        Dim sequence2 As New XmlSchemaSequence()

        ' <xs:element name="customerOrders" type="customerOrderType" minOccurs="0" maxOccurs="unbounded" />
        Dim customerOrders As New XmlSchemaElement()
        customerOrders.MinOccurs = 0
        customerOrders.MaxOccursString = "unbounded"
        customerOrders.Name = "customerOrders"
        customerOrders.SchemaTypeName = New XmlQualifiedName("customerOrderType", "")

        ' </xs:sequence>
        sequence2.Items.Add(customerOrders)

        ' </xs:complexType>
        ct2.Particle = sequence2
        ordersByCustomer.SchemaType = ct2

        ' <xs:unique name="oneCustomerOrdersforEachCustomerID">
        Dim element_unique As New XmlSchemaUnique()
        element_unique.Name = "oneCustomerOrdersforEachCustomerID"

        ' <xs:selector xpath="customerOrders"/>
        element_unique.Selector = New XmlSchemaXPath()
        element_unique.Selector.XPath = "customerOrders"

        ' <xs:field xpath="@customerID"/>
        Dim field As New XmlSchemaXPath()
        field.XPath = "@customerID"

        ' </xs:unique>
        element_unique.Fields.Add(field)
        ordersByCustomer.Constraints.Add(element_unique)

        ' </xs:element>
        schema.Items.Add(ordersByCustomer)

        Dim schemaSet As New XmlSchemaSet()
        AddHandler schemaSet.ValidationEventHandler, AddressOf ValidationCallbackOne

        schemaSet.Add(schema)
        schemaSet.Compile()

        Dim compiledSchema As XmlSchema = Nothing

        For Each schema1 As XmlSchema In schemaSet.Schemas()
            compiledSchema = schema1
        Next

        Dim nsmgr As New XmlNamespaceManager(New NameTable())
        nsmgr.AddNamespace("xs", "http://www.w3.org/2001/XMLSchema")
        compiledSchema.Write(Console.Out, nsmgr)

    End Sub

    Public Shared Sub ValidationCallbackOne(ByVal sender As Object, ByVal args As ValidationEventArgs)
        Console.WriteLine(args.Message)
    End Sub
End Class

O seguinte ficheiro XML é gerado para este exemplo de código.

<?xml version="1.0" encoding="IBM437"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:complexType name="customerOrderType">
        <xs:sequence>
            <xs:element name="item" minOccurs="0" maxOccurs="unbounded">
                <xs:complexType>
                    <xs:attribute name="itemID" type="xs:string"/>
                </xs:complexType>
            </xs:element>
        </xs:sequence>
        <xs:attribute name="CustomerID" type="xs:string"/>
    </xs:complexType>

    <xs:element name="ordersByCustomer">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="customerOrders" type="customerOrderType" minOccurs="0" maxOccurs="unbounded" />
            </xs:sequence>
        </xs:complexType>
        <xs:unique name="oneCustomerOrdersforEachCustomerID">
            <xs:selector xpath="customerOrders"/>
            <xs:field xpath="@customerID"/>
        </xs:unique>
    </xs:element>
</xs:schema>

Observações

Especifica que um valor de atributo ou elemento (ou uma combinação de valores de atributo ou elemento) deve ser único dentro do âmbito especificado. O nome da restrição deve ser único dentro de um esquema.

Construtores

Name Description
XmlSchemaUnique()

Inicializa uma nova instância da XmlSchemaUnique classe.

Propriedades

Name Description
Annotation

Obtém ou definem a annotation propriedade.

(Herdado de XmlSchemaAnnotated)
Fields

Obtém a coleção de campos que se aplicam como filhos para o seletor de expressões XML Path Language (XPath).

(Herdado de XmlSchemaIdentityConstraint)
Id

Obtém ou define o id da cadeia.

(Herdado de XmlSchemaAnnotated)
LineNumber

Obtém ou define o número da linha no ficheiro a que o schema elemento se refere.

(Herdado de XmlSchemaObject)
LinePosition

Obtém ou define a posição da linha no ficheiro a que o schema elemento se refere.

(Herdado de XmlSchemaObject)
Name

Recebe ou define o nome da restrição identidade.

(Herdado de XmlSchemaIdentityConstraint)
Namespaces

Obtém ou define o XmlSerializerNamespaces para usar com este objeto de esquema.

(Herdado de XmlSchemaObject)
Parent

Obtém ou define o pai deste XmlSchemaObject.

(Herdado de XmlSchemaObject)
QualifiedName

Recebe o nome qualificado da restrição identidade, que detém o valor pós-compilação da QualifiedName propriedade.

(Herdado de XmlSchemaIdentityConstraint)
Selector

Recebe ou define o elemento de expressão selector XPath.

(Herdado de XmlSchemaIdentityConstraint)
SourceUri

Obtém ou define a localização de origem do ficheiro que carregou o esquema.

(Herdado de XmlSchemaObject)
UnhandledAttributes

Obtém ou define os atributos qualificados que não pertencem ao namespace de destino do esquema atual.

(Herdado de XmlSchemaAnnotated)

Métodos

Name Description
Equals(Object)

Determina se o objeto especificado é igual ao objeto atual.

(Herdado de Object)
GetHashCode()

Serve como função de hash predefinida.

(Herdado de Object)
GetType()

Obtém o Type da instância atual.

(Herdado de Object)
MemberwiseClone()

Cria uma cópia superficial do atual Object.

(Herdado de Object)
ToString()

Devolve uma cadeia que representa o objeto atual.

(Herdado de Object)

Aplica-se a