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XmlWriter.WriteDocType Method

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

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

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

Parameters

name
Type: System.String

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

pubid
Type: System.String

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

sysid
Type: System.String

If pubid is Nothing and sysid is non-null it writes SYSTEM "sysid" where sysid is replaced with the value of this argument.

subset
Type: System.String

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

ExceptionCondition
InvalidOperationException

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

ArgumentException

The value for name would result in invalid XML.

InvalidOperationException

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.”

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.

Security noteSecurity Note

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.

The following example writes an XML file representing a book.

Option Strict
Option Explicit

Imports System
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 'Main 
End Class 'Sample

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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