XmlSchemaUnique Class

Reference

Definition

Namespace:: System.Xml.Schema

Assembly:: System.Xml.ReaderWriter.dll

Assembly:: System.Xml.dll

Assembly:: netstandard.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Represents the unique element from XML Schema as specified by the World Wide Web Consortium (W3C). This class can be used to identify a unique constraint among a set of elements.

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

Inheritance: Object

XmlSchemaObject

XmlSchemaAnnotated

XmlSchemaIdentityConstraint
XmlSchemaUnique

Examples

The following example shows the use of the XmlSchemaUnique class.

#using <System.Xml.dll>

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

ref class XMLSchemaExamples
{
private:
    static void ValidationCallbackOne(Object^ sender, ValidationEventArgs^ args)
    {
        Console::WriteLine(args->Message);
    }

public:
    static void Main()
    {
        XmlSchema^ schema = gcnew XmlSchema();

        // <xs:complexType name="customerOrderType">
        XmlSchemaComplexType^ customerOrderType = gcnew XmlSchemaComplexType();
        customerOrderType->Name = "customerOrderType";

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

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

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

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

        customerOrderType->Attributes->Add(CustomerID);

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

        // <xs:element name="ordersByCustomer">
        XmlSchemaElement^ ordersByCustomer = gcnew XmlSchemaElement();
        ordersByCustomer->Name = "ordersByCustomer";

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

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

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

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

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

        // <xs:unique name="oneCustomerOrdersforEachCustomerID">
        XmlSchemaUnique^ element_unique = gcnew XmlSchemaUnique();
        element_unique->Name = "oneCustomerOrdersforEachCustomerID";

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

        // <xs:field xpath="@customerID"/>
        XmlSchemaXPath^ field = gcnew XmlSchemaXPath();
        field->XPath = "@customerID";

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

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

        XmlSchemaSet^ schemaSet = gcnew XmlSchemaSet();
        schemaSet->ValidationEventHandler += gcnew ValidationEventHandler(ValidationCallbackOne);
        schemaSet->Add(schema);
        schemaSet->Compile();

        XmlSchema^ compiledSchema = nullptr;

        for each (XmlSchema^ schema1 in schemaSet->Schemas())
        {
            compiledSchema = schema1;
        }

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

int main()
{
    XMLSchemaExamples::Main();
    return 0;
}

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

The following XML file is generated for this code example.

<?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>

Remarks

Specifies that an attribute or element value (or a combination of attribute or element values) must be unique within the specified scope. The constraint name must be unique within a schema.

Constructors

XmlSchemaUnique()

Initializes a new instance of the XmlSchemaUnique class.

Properties

Annotation	Gets or sets the `annotation` property. (Inherited from XmlSchemaAnnotated)
Fields	Gets the collection of fields that apply as children for the XML Path Language (XPath) expression selector. (Inherited from XmlSchemaIdentityConstraint)
Id	Gets or sets the string id. (Inherited from XmlSchemaAnnotated)
LineNumber	Gets or sets the line number in the file to which the `schema` element refers. (Inherited from XmlSchemaObject)
LinePosition	Gets or sets the line position in the file to which the `schema` element refers. (Inherited from XmlSchemaObject)
Name	Gets or sets the name of the identity constraint. (Inherited from XmlSchemaIdentityConstraint)
Namespaces	Gets or sets the XmlSerializerNamespaces to use with this schema object. (Inherited from XmlSchemaObject)
Parent	Gets or sets the parent of this XmlSchemaObject. (Inherited from XmlSchemaObject)
QualifiedName	Gets the qualified name of the identity constraint, which holds the post-compilation value of the `QualifiedName` property. (Inherited from XmlSchemaIdentityConstraint)
Selector	Gets or sets the XPath expression `selector` element. (Inherited from XmlSchemaIdentityConstraint)
SourceUri	Gets or sets the source location for the file that loaded the schema. (Inherited from XmlSchemaObject)
UnhandledAttributes	Gets or sets the qualified attributes that do not belong to the current schema's target namespace. (Inherited from XmlSchemaAnnotated)

Methods

Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)

Applies to

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