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XmlSchemaChoice Class

Represents the choice element (compositor) from the XML Schema as specified by the World Wide Web Consortium (W3C). The choice allows only one of its children to appear in an instance.

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

'Declaration
Public Class XmlSchemaChoice _
	Inherits XmlSchemaGroupBase
'Usage
Dim instance As XmlSchemaChoice

The following example creates a choice element.

Option Strict On
Option Explicit On

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

Class XMLSchemaExamples
    Public Shared Sub Main()
        Dim schema As New XmlSchema()

        ' <xs:element name="selected"/> 
        Dim xeSelected As New XmlSchemaElement()
        xeSelected.Name = "selected"
        schema.Items.Add(xeSelected)

        ' <xs:element name="unselected"/> 
        Dim xeUnselected As New XmlSchemaElement()
        xeUnselected.Name = "unselected"
        schema.Items.Add(xeUnselected)

        ' <xs:element name="dimpled"/> 
        Dim xeDimpled As New XmlSchemaElement()
        xeDimpled.Name = "dimpled"
        schema.Items.Add(xeDimpled)

        ' <xs:element name="perforated"/> 
        Dim xePerforated As New XmlSchemaElement()
        xePerforated.Name = "perforated"
        schema.Items.Add(xePerforated)

        ' <xs:complexType name="chadState"> 
        Dim chadState As New XmlSchemaComplexType()
        schema.Items.Add(chadState)
        chadState.Name = "chadState" 

        ' <xs:choice minOccurs="1" maxOccurs="1"> 
        Dim choice As New XmlSchemaChoice()
        chadState.Particle = choice
        choice.MinOccurs = 1
        choice.MaxOccurs = 1

        ' <xs:element ref="selected"/> 
        Dim elementSelected As New XmlSchemaElement()
        choice.Items.Add(elementSelected)
        elementSelected.RefName = New XmlQualifiedName("selected")

        ' <xs:element ref="unselected"/> 
        Dim elementUnselected As New XmlSchemaElement()
        choice.Items.Add(elementUnselected)
        elementUnselected.RefName = New XmlQualifiedName("unselected")

        ' <xs:element ref="dimpled"/> 
        Dim elementDimpled As New XmlSchemaElement()
        choice.Items.Add(elementDimpled)
        elementDimpled.RefName = New XmlQualifiedName("dimpled")

        ' <xs:element ref="perforated"/> 
        Dim elementPerforated As New XmlSchemaElement()
        choice.Items.Add(elementPerforated)
        elementPerforated.RefName = New XmlQualifiedName("perforated")

        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 'Main


    Public Shared Sub ValidationCallbackOne(ByVal sender As Object, ByVal args As ValidationEventArgs)

        Console.WriteLine(args.Message)
    End Sub 'ValidationCallbackOne
End Class 'XMLSchemaExamples

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

<?xml version="1.0" encoding="IBM437"?>
<xs:schema  xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:element name="selected"/>
    <xs:element name="unselected"/>
    <xs:element name="dimpled"/>
    <xs:element name="perforated"/>

    <xs:complexType name="chadState">
        <xs:choice minOccurs="1" maxOccurs="1">
            <xs:element ref="selected"/>
            <xs:element ref="unselected"/>
            <xs:element ref="dimpled"/>
            <xs:element ref="perforated"/>
        </xs:choice>
    </xs:complexType>
</xs:schema>

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

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

.NET Framework

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

.NET Compact Framework

Supported in: 3.5, 2.0

XNA Framework

Supported in: 3.0, 2.0, 1.0
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