XslTransform.Transform Method (IXPathNavigable, XsltArgumentList, XmlWriter, XmlResolver)


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Transforms the XML data in the IXPathNavigable using the specified args and outputs the result to an XmlWriter.

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

public void Transform(
	IXPathNavigable input,
	XsltArgumentList args,
	XmlWriter output,
	XmlResolver resolver


Type: System.Xml.XPath.IXPathNavigable

An object implementing the IXPathNavigable interface. In the .NET Framework, this can be either an XmlNode (typically an XmlDocument), or an XPathDocument containing the data to be transformed.

Type: System.Xml.Xsl.XsltArgumentList

An XsltArgumentList containing the namespace-qualified arguments used as input to the transformation.

Type: System.Xml.XmlWriter

The XmlWriter to which you want to output.

Type: System.Xml.XmlResolver

The XmlResolver used to resolve the XSLT document() function. If this is null, the document() function is not resolved.

The XmlResolver is not cached after the Transform method completes.

Exception Condition

There was an error processing the XSLT transformation.

Note: This is a change in behavior from earlier versions. An XsltException is thrown if you are using Microsoft .NET Framework version 1.1 or earlier.


The XslTransform class is obsolete in the .NET Framework version 2.0. The XslCompiledTransform class is the new XSLT processor. For more information, see Using the XslCompiledTransform Class and Migrating From the XslTransform Class.

XslTransform supports the XSLT 1.0 syntax. The XSLT style sheet must include the namespace declaration xmlns:xsl= http://www.w3.org/1999/XSL/Transform.

The args are matched with the xsl:param elements defined in the style sheet. The xsl:output element is not supported when outputting to an XmlWriter (xsl:output is ignored). See Outputs from an XslTransform for more information.

Transformations apply to the document as a whole. In other words, if you pass in a node other than the document root node, this does not prevent the transformation process from accessing all nodes in the loaded document. To transform a node fragment, you must create an XmlDocument containing just the node fragment and pass that XmlDocument to the Transform method.

The following example performs a transformation on a node fragment.

XslTransform xslt = new XslTransform();     
XmlDocument doc = new XmlDocument();
// Create a new document containing just the node fragment.
XmlNode testNode = doc.DocumentElement.FirstChild; 
XmlDocument tmpDoc = new XmlDocument(); 
// Pass the document containing the node fragment 
// to the Transform method.
Console.WriteLine("Passing " + tmpDoc.OuterXml + " to print_root.xsl");
xslt.Transform(tmpDoc, null, Console.Out, null);

The example uses the library.xml and print_root.xsl files as input and outputs the following to the console.

Passing <book genre="novel" ISBN="1-861001-57-5"><title>Pride And Prejudice</title></book> to print_root.xsl 
Root node is book.


  <book genre='novel' ISBN='1-861001-57-5'>
     <title>Pride And Prejudice</title>
  <book genre='novel' ISBN='1-81920-21-2'>


<style sheet version="1.0" xmlns="http://www.w3.org/1999/XSL/Transform" >
  <output method="text" />
  <template match="/">
  Root node is  <value-of select="local-name(//*[position() = 1])" /> 
</style sheet>

The following example transforms an XML document into an HTML document. It displays the ISBN, title, and price for each book in a table.

using System;
using System.IO;
using System.Xml;
using System.Xml.Xsl;
using System.Xml.XPath;

public class Sample
  private const String filename = "books.xml";
  private const String stylesheet = "output.xsl";

  public static void Main()
    //Load the stylesheet.
    XslTransform xslt = new XslTransform();

    //Load the file to transform.
    XPathDocument doc = new XPathDocument(filename);

    //Create an XmlTextWriter which outputs to the console.
    XmlTextWriter writer = new XmlTextWriter(Console.Out);

    //Transform the file and send the output to the console.
    xslt.Transform(doc, null, writer, null);


The sample uses the following two input files.


<?xml version='1.0'?>
<!-- This file represents a fragment of a book store inventory database -->
  <book genre="autobiography" publicationdate="1981" ISBN="1-861003-11-0">
    <title>The Autobiography of Benjamin Franklin</title>
  <book genre="novel" publicationdate="1967" ISBN="0-201-63361-2">
    <title>The Confidence Man</title>
  <book genre="philosophy" publicationdate="1991" ISBN="1-861001-57-6">
    <title>The Gorgias</title>


<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:template match="bookstore">
      <TABLE BORDER="2">
        <xsl:apply-templates select="book"/>
<xsl:template match="book">
    <TD><xsl:value-of select="@ISBN"/></TD>
    <TD><xsl:value-of select="title"/></TD>
    <TD><xsl:value-of select="price"/></TD>

.NET Framework
Available since 1.1
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