XmlSchemaKeyref Class

.NET Framework (current version)

This class represents the keyref element from XMLSchema as specified by the World Wide Web Consortium (W3C).

Namespace: System.Xml.Schema
Assembly: System.Xml (in System.Xml.dll)

Inheritance Hierarchy

System::Object
System.Xml.Schema::XmlSchemaObject
System.Xml.Schema::XmlSchemaAnnotated
System.Xml.Schema::XmlSchemaIdentityConstraint
System.Xml.Schema::XmlSchemaKeyref

Syntax

C++

public ref class XmlSchemaKeyref : XmlSchemaIdentityConstraint

Constructors

	Name	Description
	XmlSchemaKeyref()	Initializes a new instance of the XmlSchemaKeyref class.

Properties

	Name	Description
	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.)
	Refer	Gets or sets the name of the key that this constraint refers to in another simple or complex type.
	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

	Name	Description
	Equals(Object^)	Determines whether the specified object is equal to the current object.(Inherited from Object.)
	Finalize()	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(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.)

Remarks

Specifies that an attribute or element value (or set of values) has a correspondence with those of the specified key or unique element. The constraint name must be unique within a schema.

Examples

The following example creates a key element.

C++

#using <System.Xml.dll>
#using <System.dll>

using namespace System;
using namespace System::Collections;
using namespace System::IO;
using namespace System::Xml;
using namespace System::Xml::Xsl;
using namespace System::Xml::Schema;
public ref class XmlSchemaObjectGenerator
{
private:
    static void ValidationCallback( Object^ /*sender*/, ValidationEventArgs^ args )
    {
        if ( args->Severity == XmlSeverityType::Warning )
            Console::Write( "WARNING: " );
        else
            if ( args->Severity == XmlSeverityType::Error )
                Console::Write( "ERROR: " );

        Console::WriteLine( args->Message );
    }

    // XmlSchemaObjectGenerator
    int main()
    {
        XmlTextReader^ tr = gcnew XmlTextReader( "empty.xsd" );
        XmlSchema^ schema = XmlSchema::Read( tr, gcnew ValidationEventHandler( XmlSchemaObjectGenerator::ValidationCallback ) );
        schema->ElementFormDefault = XmlSchemaForm::Qualified;
        schema->TargetNamespace = "http://www.example.com/Report";
        {
            XmlSchemaElement^ element = gcnew XmlSchemaElement;
            element->Name = "purchaseReport";
            XmlSchemaComplexType^ element_complexType = gcnew XmlSchemaComplexType;
            XmlSchemaSequence^ element_complexType_sequence = gcnew XmlSchemaSequence;
            {
                XmlSchemaElement^ element_complexType_sequence_element = gcnew XmlSchemaElement;
                element_complexType_sequence_element->Name = "region";
                element_complexType_sequence_element->SchemaTypeName = gcnew XmlQualifiedName( "String*","http://www.w3.org/2001/XMLSchema" );
                {
                    XmlSchemaKeyref^ element_complexType_sequence_element_keyref = gcnew XmlSchemaKeyref;
                    element_complexType_sequence_element_keyref->Name = "dummy2";
                    element_complexType_sequence_element_keyref->Selector = gcnew XmlSchemaXPath;
                    element_complexType_sequence_element_keyref->Selector->XPath = "r:zip/r:part";
                    {
                        XmlSchemaXPath^ field = gcnew XmlSchemaXPath;
                        field->XPath = "@number";
                        element_complexType_sequence_element_keyref->Fields->Add( field );
                    }
                    element_complexType_sequence_element_keyref->Refer = gcnew XmlQualifiedName( "pNumKey","http://www.example.com/Report" );
                    element_complexType_sequence_element->Constraints->Add( element_complexType_sequence_element_keyref );
                }
                element_complexType_sequence->Items->Add( element_complexType_sequence_element );
            }
            element_complexType->Particle = element_complexType_sequence;
            {
                XmlSchemaAttribute^ element_complexType_attribute = gcnew XmlSchemaAttribute;
                element_complexType_attribute->Name = "periodEnding";
                element_complexType_attribute->SchemaTypeName = gcnew XmlQualifiedName( "date","http://www.w3.org/2001/XMLSchema" );
                element_complexType->Attributes->Add( element_complexType_attribute );
            }
            element->SchemaType = element_complexType;
            {
                XmlSchemaKey^ element_key = gcnew XmlSchemaKey;
                element_key->Name = "pNumKey";
                element_key->Selector = gcnew XmlSchemaXPath;
                element_key->Selector->XPath = "r:parts/r:part";
                {
                    XmlSchemaXPath^ field = gcnew XmlSchemaXPath;
                    field->XPath = "@number";
                    element_key->Fields->Add( field );
                }
                element->Constraints->Add( element_key );
            }
            schema->Items->Add( element );
        }
        schema->Write( Console::Out );

        return 0;
    } // main
};

The following XML file is generated for the preceding code example.

XML

<?xml version="1.0" encoding="IBM437"?>
<xs:schema xmlns:r="http://www.example.com/Report" elementFormDefault="qualified" targetNamespace="http://www.example.com/Report" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="purchaseReport">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="region" type="xs:string">
          <xs:keyref name="dummy2" refer="r:pNumKey">
            <xs:selector xpath="r:zip/r:part" />
            <xs:field xpath="@number" />
          </xs:keyref>
        </xs:element>
      </xs:sequence>
      <xs:attribute name="periodEnding" type="xs:date" />
    </xs:complexType>
    <xs:key name="pNumKey">
      <xs:selector xpath="r:parts/r:part" />
      <xs:field xpath="@number" />
    </xs:key>
  </xs:element>
</xs:schema>

Version Information

.NET Framework
Available since 1.1

Thread Safety

Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.