XmlWriter.WriteDocType(String, String, String, String) Method

Reference

Definition

Namespace:: System.Xml

Assembly:: System.Xml.ReaderWriter.dll

Assembly:: System.Xml.dll

Assembly:: netstandard.dll

Source:: XmlWriter.cs

Source:: XmlWriter.cs

Source:: XmlWriter.cs

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

When overridden in a derived class, writes the DOCTYPE declaration with the specified name and optional attributes.

public:
 abstract void WriteDocType(System::String ^ name, System::String ^ pubid, System::String ^ sysid, System::String ^ subset);

public abstract void WriteDocType (string name, string pubid, string sysid, string subset);

public abstract void WriteDocType (string name, string? pubid, string? sysid, string? subset);

abstract member WriteDocType : string * string * string * string -> unit

Public MustOverride Sub WriteDocType (name As String, pubid As String, sysid As String, subset As String)

Parameters

name: String

The name of the DOCTYPE. This must be non-empty.

pubid: String

If non-null it also writes PUBLIC "pubid" "sysid" where pubid and sysid are replaced with the value of the given arguments.

sysid: String

If pubid is null and sysid is non-null it writes SYSTEM "sysid" where sysid is replaced with the value of this argument.

subset: String

If non-null it writes [subset] where subset is replaced with the value of this argument.

Exceptions

InvalidOperationException

This method was called outside the prolog (after the root element).

-or-

An XmlWriter method was called before a previous asynchronous operation finished. In this case, InvalidOperationException is thrown with the message "An asynchronous operation is already in progress."

ArgumentException

The value for name would result in invalid XML.

Examples

The following example writes an XML file representing a book.

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

public class Sample {

  private const string filename = "sampledata.xml";

  public static void Main() {

     XmlWriterSettings settings = new XmlWriterSettings();
     settings.Indent = true;
     XmlWriter writer = XmlWriter.Create(filename, settings);

     // Write the Processing Instruction node.
     String PItext="type=\"text/xsl\" href=\"book.xsl\"";
     writer.WriteProcessingInstruction("xml-stylesheet", PItext);

     // Write the DocumentType node.
     writer.WriteDocType("book", null , null, "<!ENTITY h \"hardcover\">");

     // Write a Comment node.
     writer.WriteComment("sample XML");

     // Write the root element.
     writer.WriteStartElement("book");

     // Write the genre attribute.
     writer.WriteAttributeString("genre", "novel");

     // Write the ISBN attribute.
     writer.WriteAttributeString("ISBN", "1-8630-014");

     // Write the title.
     writer.WriteElementString("title", "The Handmaid's Tale");

     // Write the style element.
     writer.WriteStartElement("style");
     writer.WriteEntityRef("h");
     writer.WriteEndElement();

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

     // Write CDATA.
     writer.WriteCData("Prices 15% off!!");

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

     writer.WriteEndDocument();

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

Option Strict
Option Explicit

Imports System.IO
Imports System.Xml

Public Class Sample
    Private Const filename As String = "sampledata.xml"
    
  Public Shared Sub Main()

     Dim settings As XmlWriterSettings = new XmlWriterSettings()
     settings.Indent = true
     Dim writer As XmlWriter = XmlWriter.Create(filename, settings)
        
     ' Write the Processing Instruction node.
     Dim PItext As String = "type=""text/xsl"" href=""book.xsl"""
     writer.WriteProcessingInstruction("xml-stylesheet", PItext)
        
     'Write the DocumentType node.
     writer.WriteDocType("book", Nothing, Nothing, "<!ENTITY h ""hardcover"">")
        
     ' Write a Comment node.
     writer.WriteComment("sample XML")
        
     ' Write the root element.
     writer.WriteStartElement("book")
        
     ' Write the genre attribute
     writer.WriteAttributeString("genre", "novel")
        
     ' Write the ISBN attribute.
     writer.WriteAttributeString("ISBN", "1-8630-014")
        
     ' Write the title.
     writer.WriteElementString("title", "The Handmaid's Tale")
        
     ' Write the style element.
     writer.WriteStartElement("style")
     writer.WriteEntityRef("h")
     writer.WriteEndElement()
       
     ' Write the price.
     writer.WriteElementString("price", "19.95")
        
     ' Write CDATA.
     writer.WriteCData("Prices 15% off!!")
        
     ' Write the close tag for the root element.
     writer.WriteEndElement()
        
     writer.WriteEndDocument()
        
     ' Write the XML to file and close the writer
     writer.Flush()
     writer.Close()
        
    End Sub
End Class

Remarks

This method does not check for invalid characters in pubid, sysid or subset. It also does not check that the internal subset is well-formed.

Important

The XmlWriter does not validate the data that is passed to the WriteDocType method. You should not pass arbitrary data to this method.

For the asynchronous version of this method, see WriteDocTypeAsync.

Applies to

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