XmlWriter.WriteComment Method (String)

 

When overridden in a derived class, writes out a comment <!--...--> containing the specified text.

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

Public MustOverride Sub WriteComment (
	text As String
)

Parameters

text
Type: System.String

Text to place inside the comment.

Exception Condition
ArgumentException

The text would result in a non-well-formed XML document.

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.”

If text is either null or String.Empty, this method writes a comment with no data content, for example <!---->.

If text contains an invalid sequence of two dashes "--" the XmlWriter can either throw an ArgumentException (XmlTextWriter objects) or insert a space between the dashes "- -" so that the text is a valid XML comment (XmlWriter objects created by the Create method).

For the asynchronous version of this method, see WriteCommentAsync.

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

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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