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XmlSchemaKeyref Class

This class represents the keyref element from XMLSchema as specified by the .

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

'Declaration
Public Class XmlSchemaKeyref _
	Inherits XmlSchemaIdentityConstraint

The XmlSchemaKeyref type exposes the following members.

  NameDescription
Public methodSupported by the XNA FrameworkXmlSchemaKeyrefInitializes a new instance of the XmlSchemaKeyref class.
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  NameDescription
Public propertySupported by the XNA FrameworkAnnotationGets or sets the annotation property. (Inherited from XmlSchemaAnnotated.)
Public propertySupported by the XNA FrameworkFieldsGets the collection of fields that apply as children for the XML Path Language (XPath) expression selector. (Inherited from XmlSchemaIdentityConstraint.)
Public propertySupported by the XNA FrameworkIdGets or sets the string id. (Inherited from XmlSchemaAnnotated.)
Public propertySupported by the XNA FrameworkLineNumberGets or sets the line number in the file to which the schema element refers. (Inherited from XmlSchemaObject.)
Public propertySupported by the XNA FrameworkLinePositionGets or sets the line position in the file to which the schema element refers. (Inherited from XmlSchemaObject.)
Public propertySupported by the XNA FrameworkNameGets or sets the name of the identity constraint. (Inherited from XmlSchemaIdentityConstraint.)
Public propertySupported by the XNA FrameworkNamespacesGets or sets the XmlSerializerNamespaces to use with this schema object. (Inherited from XmlSchemaObject.)
Public propertySupported by the XNA FrameworkParentGets or sets the parent of this XmlSchemaObject. (Inherited from XmlSchemaObject.)
Public propertySupported by the XNA FrameworkQualifiedNameGets the qualified name of the identity constraint, which holds the post-compilation value of the QualifiedName property. (Inherited from XmlSchemaIdentityConstraint.)
Public propertySupported by the XNA FrameworkReferGets or sets the name of the key that this constraint refers to in another simple or complex type.
Public propertySupported by the XNA FrameworkSelectorGets or sets the XPath expression selector element. (Inherited from XmlSchemaIdentityConstraint.)
Public propertySupported by the XNA FrameworkSourceUriGets or sets the source location for the file that loaded the schema. (Inherited from XmlSchemaObject.)
Public propertySupported by the XNA FrameworkUnhandledAttributesGets or sets the qualified attributes that do not belong to the current schema's target namespace. (Inherited from XmlSchemaAnnotated.)
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  NameDescription
Public methodSupported by the XNA FrameworkEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodSupported by the XNA FrameworkFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by the XNA FrameworkGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodSupported by the XNA FrameworkGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodSupported by the XNA FrameworkMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodSupported by the XNA FrameworkToStringReturns a string that represents the current object. (Inherited from Object.)
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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.

The following example creates a key element.


Imports System
Imports System.Collections
Imports System.IO
Imports System.Xml
Imports System.Xml.Xsl
Imports System.Xml.Schema

Public Class XmlSchemaObjectGenerator

   Private Shared Sub ValidationCallback(sender As Object, args As ValidationEventArgs)

      If args.Severity = XmlSeverityType.Warning Then
         Console.Write("WARNING: ")
      Else
         If args.Severity = XmlSeverityType.Error Then
            Console.Write("ERROR: ")
         End If 
      End If
      Console.WriteLine(args.Message)
   End Sub 'ValidationCallback



   Public Shared Sub Main()


      Dim tr As New XmlTextReader("empty.xsd")
      Dim schema As XmlSchema = XmlSchema.Read(tr, New ValidationEventHandler(AddressOf ValidationCallback))

      schema.ElementFormDefault = XmlSchemaForm.Qualified

      schema.TargetNamespace = "http://www.example.com/Report"

      If (True) Then

         Dim element As New XmlSchemaElement()
         element.Name = "purchaseReport"

         Dim element_complexType As New XmlSchemaComplexType()

         Dim element_complexType_sequence As New XmlSchemaSequence()

         If (True) Then

            Dim element_complexType_sequence_element As New XmlSchemaElement()
            element_complexType_sequence_element.Name = "region"
            element_complexType_sequence_element.SchemaTypeName = New XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema")

            If (True) Then

               Dim element_complexType_sequence_element_keyref As New XmlSchemaKeyref()
               element_complexType_sequence_element_keyref.Name = "dummy2"
               element_complexType_sequence_element_keyref.Selector = New XmlSchemaXPath()
               element_complexType_sequence_element_keyref.Selector.XPath = "r:zip/r:part"

               If (True) Then
                  Dim field As New XmlSchemaXPath()

                  field.XPath = "@number"
                  element_complexType_sequence_element_keyref.Fields.Add(field)
               End If
               element_complexType_sequence_element_keyref.Refer = New XmlQualifiedName("pNumKey", "http://www.example.com/Report")
               element_complexType_sequence_element.Constraints.Add(element_complexType_sequence_element_keyref)
            End If
            element_complexType_sequence.Items.Add(element_complexType_sequence_element)
         End If
         element_complexType.Particle = element_complexType_sequence

         If (True) Then

            Dim element_complexType_attribute As New XmlSchemaAttribute()
            element_complexType_attribute.Name = "periodEnding"
            element_complexType_attribute.SchemaTypeName = New XmlQualifiedName("date", "http://www.w3.org/2001/XMLSchema")
            element_complexType.Attributes.Add(element_complexType_attribute)
         End If
         element.SchemaType = element_complexType

         If (True) Then

            Dim element_key As New XmlSchemaKey()
            element_key.Name = "pNumKey"
            element_key.Selector = New XmlSchemaXPath()
            element_key.Selector.XPath = "r:parts/r:part"

            If (True) Then
               Dim field As New XmlSchemaXPath()

               field.XPath = "@number"
               element_key.Fields.Add(field)
            End If
            element.Constraints.Add(element_key)
         End If

         schema.Items.Add(element)
      End If

      schema.Write(Console.Out)
   End Sub 'Main 
End Class 'XmlSchemaObjectGenerator 

' Main() 

'XmlSchemaObjectGenerator


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


<?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>


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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

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