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WriteComment Method
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XmlWriter.WriteComment Method

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

Namespace:  System.Xml
Assemblies:   System.Xml (in System.Xml.dll)
  System.Xml.ReaderWriter (in System.Xml.ReaderWriter.dll)

public abstract void WriteComment(
	string text
)

Parameters

text
Type: System.String

Text to place inside the comment.

ExceptionCondition
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.

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();  
  }

}

.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

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
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