XmlTextWriter.LookupPrefix(String) メソッド

定義

名前空間:

System.Xml

アセンブリ:

System.Xml.ReaderWriter.dll

アセンブリ:

System.Xml.dll

アセンブリ:

netstandard.dll

名前空間 URI の現在の名前空間スコープで定義されたものに最も近いプリフィックスを返します。

public:
 override System::String ^ LookupPrefix(System::String ^ ns);

public override string? LookupPrefix (string ns);

public override string LookupPrefix (string ns);

override this.LookupPrefix : string -> string

Public Overrides Function LookupPrefix (ns As String) As String

パラメーター

ns

String

検索する対象となるプリフィックスを持つ名前空間 URI。

戻り値

String

一致するプリフィックス。 一致する名前空間 URI が現在のスコープで見つからない場合は null。

例外

ArgumentException

ns が null または String.Empty です。

例

次の例では、書籍を書き出します。

#using <System.Xml.dll>

using namespace System;
using namespace System::IO;
using namespace System::Xml;
int main()
{
   String^ filename = "sampledata.xml";
   XmlTextWriter^ writer = gcnew XmlTextWriter( filename, nullptr );
   
   //Use indenting for readability.
   writer->Formatting = Formatting::Indented;
   writer->WriteComment( "sample XML fragment" );
   
   //Write an element (this one is the root).
   writer->WriteStartElement( "bookstore" );
   
   //Write the namespace declaration.
   writer->WriteAttributeString( "xmlns", "bk", nullptr, "urn:samples" );
   writer->WriteStartElement( "book" );
   
   //Lookup the prefix and then write the ISBN attribute.
   String^ prefix = writer->LookupPrefix( "urn:samples" );
   writer->WriteStartAttribute( prefix, "ISBN", "urn:samples" );
   writer->WriteString( "1-861003-78" );
   writer->WriteEndAttribute();
   
   //Write the title.
   writer->WriteStartElement( "title" );
   writer->WriteString( "The Handmaid's Tale" );
   writer->WriteEndElement();
   
   //Write the price.
   writer->WriteElementString( "price", "19.95" );
   
   //Write the style element.
   writer->WriteStartElement( prefix, "style", "urn:samples" );
   writer->WriteString( "hardcover" );
   writer->WriteEndElement();
   
   //Write the end tag for the book element.
   writer->WriteEndElement();
   
   //Write the close tag for the root element.
   writer->WriteEndElement();
   
   //Write the XML to file and close the writer.
   writer->Flush();
   writer->Close();
   
   //Read the file back in and parse to ensure well formed XML.
   XmlDocument^ doc = gcnew XmlDocument;
   
   //Preserve white space for readability.
   doc->PreserveWhitespace = true;
   
   //Load the file
   doc->Load( filename );
   
   //Write the XML content to the console.
   Console::Write( doc->InnerXml );
}

using System;
using System.IO;
using System.Xml;

public class Sample
{
  private const string filename = "sampledata.xml";

  public static void Main()
  {

     XmlTextWriter writer = new XmlTextWriter (filename, null);
     //Use indenting for readability.
     writer.Formatting = Formatting.Indented;

     writer.WriteComment("sample XML fragment");

     //Write an element (this one is the root).
     writer.WriteStartElement("bookstore");

     //Write the namespace declaration.
     writer.WriteAttributeString("xmlns", "bk", null, "urn:samples");

     writer.WriteStartElement("book");

     //Lookup the prefix and then write the ISBN attribute.
     string prefix = writer.LookupPrefix("urn:samples");
     writer.WriteStartAttribute(prefix, "ISBN", "urn:samples");
     writer.WriteString("1-861003-78");
     writer.WriteEndAttribute();

     //Write the title.
     writer.WriteStartElement("title");
     writer.WriteString("The Handmaid's Tale");
     writer.WriteEndElement();

     //Write the price.
     writer.WriteElementString("price", "19.95");

     //Write the style element.
     writer.WriteStartElement(prefix, "style", "urn:samples");
     writer.WriteString("hardcover");
     writer.WriteEndElement();

     //Write the end tag for the book element.
     writer.WriteEndElement();

     //Write the close tag for the root element.
     writer.WriteEndElement();

     //Write the XML to file and close the writer.
     writer.Flush();
     writer.Close();

     //Read the file back in and parse to ensure well formed XML.
     XmlDocument doc = new XmlDocument();
     //Preserve white space for readability.
     doc.PreserveWhitespace = true;
     //Load the file
     doc.Load(filename);

     //Write the XML content to the console.
     Console.Write(doc.InnerXml);
  }
}

Option Strict
Option Explicit

Imports System.IO
Imports System.Xml

Public Class Sample
    Private Shared filename As String = "sampledata.xml"
    Public Shared Sub Main()
        
        Dim writer As New XmlTextWriter(filename, Nothing)
        'Use indenting for readability.
        writer.Formatting = Formatting.Indented
        
        writer.WriteComment("sample XML fragment")
        
        'Write an element (this one is the root).
        writer.WriteStartElement("bookstore")
        
        'Write the namespace declaration.
        writer.WriteAttributeString("xmlns", "bk", Nothing, "urn:samples")
        
        writer.WriteStartElement("book")
        
        'Lookup the prefix and then write the ISBN attribute.
        Dim prefix As String = writer.LookupPrefix("urn:samples")
        writer.WriteStartAttribute(prefix, "ISBN", "urn:samples")
        writer.WriteString("1-861003-78")
        writer.WriteEndAttribute()
        
        'Write the title.
        writer.WriteStartElement("title")
        writer.WriteString("The Handmaid's Tale")
        writer.WriteEndElement()
        
        'Write the price.
        writer.WriteElementString("price", "19.95")
        
        'Write the style element.
        writer.WriteStartElement(prefix, "style", "urn:samples")
        writer.WriteString("hardcover")
        writer.WriteEndElement()
        
        'Write the end tag for the book element.
        writer.WriteEndElement()
        
        'Write the close tag for the root element.
        writer.WriteEndElement()
        
        'Write the XML to file and close the writer.
        writer.Flush()
        writer.Close()
        
        'Read the file back in and parse to ensure well formed XML.
        Dim doc As New XmlDocument()
        'Preserve white space for readability.
        doc.PreserveWhitespace = True
        'Load the file.
        doc.Load(filename)
        
        'Write the XML content to the console.
        Console.Write(doc.InnerXml)
    End Sub
End Class

注釈

注意

.NET Framework 2.0 以降では、新しい機能を利用するために、メソッドとXmlWriterSettingsクラスをXmlWriter.Create使用してインスタンスを作成XmlWriterすることをお勧めします。