XmlWriter.LookupPrefix(String) XmlWriter.LookupPrefix(String) XmlWriter.LookupPrefix(String) XmlWriter.LookupPrefix(String) Method

定義

派生クラスでオーバーライドされると、名前空間 URI の現在の名前空間スコープで定義された最も近いプリフィックスを返します。When overridden in a derived class, returns the closest prefix defined in the current namespace scope for the namespace URI.

public:
 abstract System::String ^ LookupPrefix(System::String ^ ns);
public abstract string LookupPrefix (string ns);
abstract member LookupPrefix : string -> string
Public MustOverride Function LookupPrefix (ns As String) As String

パラメーター

ns
String String String String

検索対象のプリフィックスを持つ名前空間 URI。The namespace URI whose prefix you want to find.

戻り値

一致するプリフィックス。現在のスコープに一致する名前空間 URI が見つからない場合は nullThe matching prefix or null if no matching namespace URI is found in the current scope.

例外

nsnull または String.Empty です。ns is either null or String.Empty.

先行の非同期操作が完了する前に、XmlWriter メソッドが呼び出されました。An XmlWriter method was called before a previous asynchronous operation finished. この場合、「非同期操作が既に実行されています」というメッセージと共に InvalidOperationException がスローされます。In this case, InvalidOperationException is thrown with the message "An asynchronous operation is already in progress."

次の例は、本を書き込みます。The following example writes out a book.

#using <System.Xml.dll>

using namespace System;
using namespace System::IO;
using namespace System::Xml;
public ref class Sample
{
private:
   static String^ m_Document = L"sampledata.xml";

public:
   static void Main()
   {
      XmlWriter^ writer = nullptr;
      try
      {
         XmlWriterSettings^ settings = gcnew XmlWriterSettings;
         settings->Indent = true;
         writer = XmlWriter::Create( m_Document,settings );
         writer->WriteComment( L"sample XML fragment" );
         
         // Write an element (this one is the root).
         writer->WriteStartElement( L"book" );
         
         // Write the namespace declaration.
         writer->WriteAttributeString( L"xmlns", L"bk", nullptr, L"urn:samples" );
         
         // Write the genre attribute.
         writer->WriteAttributeString( L"genre", L"novel" );
         
         // Write the title.
         writer->WriteStartElement( L"title" );
         writer->WriteString( L"The Handmaid's Tale" );
         writer->WriteEndElement();
         
         // Write the price.
         writer->WriteElementString( L"price", L"19.95" );
         
         // Lookup the prefix and write the ISBN element.
         String^ prefix = writer->LookupPrefix( L"urn:samples" );
         writer->WriteStartElement( prefix, L"ISBN", L"urn:samples" );
         writer->WriteString( L"1-861003-78" );
         writer->WriteEndElement();
         
         // Write the style element (shows a different way to handle prefixes).
         writer->WriteElementString( L"style", L"urn:samples", L"hardcover" );
         
         // Write the close tag for the root element.
         writer->WriteEndElement();
         
         // Write the XML to file and close the writer.
         writer->Flush();
         writer->Close();
      }
      finally
      {
         if ( writer != nullptr )
                  writer->Close();
      }

   }

};

void main()
{
   Sample::Main();
}

using System;
using System.IO;
using System.Xml;
 
 public class Sample
 {
   private const string m_Document = "sampledata.xml";
 
   public static void Main() {
   
      XmlWriter writer = null;

      try {
     
        XmlWriterSettings settings = new XmlWriterSettings();
        settings.Indent = true;
        writer = XmlWriter.Create (m_Document, settings);
           
        writer.WriteComment("sample XML fragment");
     
        // Write an element (this one is the root).
        writer.WriteStartElement("book");
 
        // Write the namespace declaration.
        writer.WriteAttributeString("xmlns", "bk", null, "urn:samples");
    
        // Write the genre attribute.
        writer.WriteAttributeString("genre", "novel");
         
        // Write the title.
        writer.WriteStartElement("title");
        writer.WriteString("The Handmaid's Tale");
        writer.WriteEndElement();
               
        // Write the price.
        writer.WriteElementString("price", "19.95");
      
        // Lookup the prefix and write the ISBN element.
        string prefix = writer.LookupPrefix("urn:samples");
        writer.WriteStartElement(prefix, "ISBN", "urn:samples");
        writer.WriteString("1-861003-78");
        writer.WriteEndElement();

        // Write the style element (shows a different way to handle prefixes).
        writer.WriteElementString("style", "urn:samples", "hardcover");
 
        // Write the close tag for the root element.
        writer.WriteEndElement();
               
        // Write the XML to file and close the writer.
        writer.Flush();
        writer.Close();
      }

      finally {
        if (writer != null)
           writer.Close();
     } 
   }
 
 }
Option Strict
Option Explicit

Imports System
Imports System.IO
Imports System.Xml

Public Class Sample
    Private Shared m_Document As String = "sampledata.xml"
    
    Public Shared Sub Main()
        Dim writer As XmlWriter = Nothing
        
      Try

        Dim settings As XmlWriterSettings = new XmlWriterSettings()
        settings.Indent = true
        writer = XmlWriter.Create (m_Document, settings)
            
        writer.WriteComment("sample XML fragment")
            
        ' Write an element (this one is the root).
        writer.WriteStartElement("book")
            
        ' Write the namespace declaration.
        writer.WriteAttributeString("xmlns", "bk", Nothing, "urn:samples")
            
        ' Write the genre attribute.
        writer.WriteAttributeString("genre", "novel")
            
        ' Write the title.
        writer.WriteStartElement("title")
        writer.WriteString("The Handmaid's Tale")
        writer.WriteEndElement()
            
        ' Write the price.
        writer.WriteElementString("price", "19.95")
            
        ' Lookup the prefix and write the ISBN element.
        Dim prefix As String = writer.LookupPrefix("urn:samples")
        writer.WriteStartElement(prefix, "ISBN", "urn:samples")
        writer.WriteString("1-861003-78")
        writer.WriteEndElement()
            
        ' Write the style element (shows a different way to handle prefixes).
        writer.WriteElementString("style", "urn:samples", "hardcover")
            
        ' Write the close tag for the root element.
        writer.WriteEndElement()
            
        ' Write the XML to file and close the writer.
        writer.Flush()
        writer.Close()
        
        Finally
            If Not (writer Is Nothing) Then
                writer.Close()
            End If
        End Try

    End Sub 'Main 
End Class 'Sample

適用対象