XmlSchemaChoice クラスとは何？わかりやすく解説 Weblio辞書

XmlSchemaChoice クラス

W3C (World Wide Web Consortium) で指定された XML スキーマの choice 要素 (コンポジタ) を表します。choice では、子要素のうち、いずれか 1 つだけが出現できることを意味します。

名前空間: System.Xml.Schema
アセンブリ: System.Xml (system.xml.dll 内)
構文

Visual Basic (宣言)

Public Class XmlSchemaChoice
    Inherits XmlSchemaGroupBase

Visual Basic (使用法)

Dim instance As XmlSchemaChoice

public class XmlSchemaChoice : XmlSchemaGroupBase

C++

public ref class XmlSchemaChoice : public
 XmlSchemaGroupBase

public class XmlSchemaChoice extends XmlSchemaGroupBase

JScript

public class XmlSchemaChoice extends
 XmlSchemaGroupBase

使用例

choice 要素を作成する例を次に示します。

Visual Basic

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

using System;
using System.Xml;
using System.Xml.Schema;

class XMLSchemaExamples
{
    public static void Main()
    {

        XmlSchema schema = new XmlSchema();

        // <xs:element name="selected"/>
        XmlSchemaElement xeSelected = new XmlSchemaElement();
        xeSelected.Name = "selected";
        schema.Items.Add(xeSelected);

        // <xs:element name="unselected"/>
        XmlSchemaElement xeUnselected = new XmlSchemaElement();
        xeUnselected.Name = "unselected";
        schema.Items.Add(xeUnselected);

        // <xs:element name="dimpled"/>
        XmlSchemaElement xeDimpled = new XmlSchemaElement();
        xeDimpled.Name = "dimpled";
        schema.Items.Add(xeDimpled);

        // <xs:element name="perforated"/>
        XmlSchemaElement xePerforated = new XmlSchemaElement();
        xePerforated.Name = "perforated";
        schema.Items.Add(xePerforated);

        // <xs:complexType name="chadState">
        XmlSchemaComplexType chadState = new XmlSchemaComplexType();
        schema.Items.Add(chadState);
        chadState.Name = "chadState";

        // <xs:choice minOccurs="1" maxOccurs="1">
        XmlSchemaChoice choice = new XmlSchemaChoice();
        chadState.Particle = choice;
        choice.MinOccurs = 1;
        choice.MaxOccurs = 1;

        // <xs:element ref="selected"/>
        XmlSchemaElement elementSelected = new XmlSchemaElement();
        choice.Items.Add(elementSelected);
        elementSelected.RefName = new XmlQualifiedName("selected");

        // <xs:element ref="unselected"/>
        XmlSchemaElement elementUnselected = new XmlSchemaElement();
        choice.Items.Add(elementUnselected);
        elementUnselected.RefName = new XmlQualifiedName("unselected");

        // <xs:element ref="dimpled"/>
        XmlSchemaElement elementDimpled = new XmlSchemaElement();
        choice.Items.Add(elementDimpled);
        elementDimpled.RefName = new XmlQualifiedName("dimpled");

        // <xs:element ref="perforated"/>
        XmlSchemaElement elementPerforated = new XmlSchemaElement();
        choice.Items.Add(elementPerforated);
        elementPerforated.RefName = new XmlQualifiedName("perforated");

        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);
    }
}

前述のコード例に対して生成される XML ファイルを次に示します。

<?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>

継承階層

System.Object
   System.Xml.Schema.XmlSchemaObject
     System.Xml.Schema.XmlSchemaAnnotated
       System.Xml.Schema.XmlSchemaParticle
         System.Xml.Schema.XmlSchemaGroupBase
          System.Xml.Schema.XmlSchemaChoice

スレッドセーフ

この型の public static (Visual Basic では Shared) メンバはすべて、スレッドセーフです。インスタンスメンバの場合は、スレッドセーフであるとは限りません。

プラットフォーム

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition