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XmlSchemaSimpleTypeUnion Class

Represents the union element for simple types from XML Schema as specified by the World Wide Web Consortium (W3C). A union datatype can be used to specify the content of a simpleType. The value of the simpleType element must be any one of a set of alternative datatypes specified in the union. Union types are always derived types and must comprise at least two alternative datatypes.

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

'Declaration
Public Class XmlSchemaSimpleTypeUnion _
	Inherits XmlSchemaSimpleTypeContent
'Usage
Dim instance As XmlSchemaSimpleTypeUnion

A union type enables an element or attribute value to be one or more instances of one type drawn from the union of multiple atomic and list types.

The following example shows the use of XmlSchemaSimpleTypeUnion class.

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

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

        ' <xs:simpleType name="StringOrIntType"> 
        Dim StringOrIntType As New XmlSchemaSimpleType()
        StringOrIntType.Name = "StringOrIntType"
        schema.Items.Add(StringOrIntType)

        ' <xs:union> 
        Dim union As New XmlSchemaSimpleTypeUnion
        StringOrIntType.Content = union

        ' <xs:simpleType> 
        Dim simpleType1 As New XmlSchemaSimpleType
        union.BaseTypes.Add(simpleType1)

        ' <xs:restriction base="xs:string"/> 
        Dim restriction1 As New XmlSchemaSimpleTypeRestriction()
        restriction1.BaseTypeName = New XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema")
        simpleType1.Content = restriction1

        ' <xs:simpleType> 
        Dim simpleType2 As New XmlSchemaSimpleType()
        union.BaseTypes.Add(simpleType2)

        ' <xs:restriction base="xs:int"/> 
        Dim restriction2 As New XmlSchemaSimpleTypeRestriction()
        restriction2.BaseTypeName = New XmlQualifiedName("int", "http://www.w3.org/2001/XMLSchema")
        simpleType2.Content = restriction2


        ' <xs:element name="size" type="StringOrIntType"/> 
        Dim elementSize As New XmlSchemaElement()
        elementSize.Name = "size"
        elementSize.SchemaTypeName = New XmlQualifiedName("StringOrIntType")
        schema.Items.Add(elementSize)

        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:simpleType name="StringOrIntType">
        <xs:union>
            <xs:simpleType>
                <xs:restriction base="xs:string"/>
            </xs:simpleType>

            <xs:simpleType>
                <xs:restriction base="xs:int"/>
            </xs:simpleType>
        </xs:union>
    </xs:simpleType>

    <xs:element name="size" type="StringOrIntType"/>
</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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