XmlDataSource.OnTransforming Method

Note: This method is new in the .NET Framework version 2.0.

Raises the Transforming event before the XmlDataSource control performs an XSLT transformation on its XML data.

Namespace: System.Web.UI.WebControls
Assembly: System.Web (in system.web.dll)

protected virtual void OnTransforming (
	EventArgs e
)
protected void OnTransforming (
	EventArgs e
)
protected function OnTransforming (
	e : EventArgs
)

Parameters

e

An EventArgs that contains the event data.

Raising an event invokes the event handler through a delegate. For more information, see Consuming Events.

The OnTransforming method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.

Notes to Inheritors When overriding OnTransforming in a derived class, be sure to call the OnTransforming method of the base class so that registered delegates receive the event.

The following code example demonstrates how to use an XmlDataSource control with a TreeView control to display transformed XML data. The XML transformation is performed using the style sheet indicated by the TransformFile property. Additionally, the style sheet uses transform arguments that are passed to the data source control in an XsltArgumentList object at runtime. The code example demonstrates how to pass the XsltArgumentList object to the data source control by handling the Transforming event with a custom event handler, which is identified by name of the method set for the OnTransforming method.

<%@ Page Language="C#" %>
<%@ Import Namespace="System.Xml.Xsl" %>


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<SCRIPT runat="server">
private void TransformEventHandler(object sender, EventArgs e) {

  // Add a dynamic transformation argument.
  DateTime d = new DateTime();
  d = DateTime.Now.AddDays(20);

  // Create an XsltArgumentList.
  XsltArgumentList xslArg = new XsltArgumentList();
  xslArg.AddParam("purchdate", "", d.ToShortDateString());

  ((XmlDataSource) sender).TransformArgumentList = xslArg;
}
</SCRIPT>

<HTML>
  <BODY>
    <form runat="server">
      <asp:XmlDataSource
        id="XmlDataSource1"
        runat="server"
        datafile="bookstore.xml"
        transformfile="bookswithdiscount.xsl"
        ontransforming="TransformEventHandler" />

        <!- TreeView uses hierachical data, so the
            XmlDataSource uses an XmlHierarchicalDataSourceView
            when a TreeView is bound to it. -->

      <asp:treeview
        id="TreeView1"
        runat="server"
        datasourceid="XmlDataSource1">
        <databindings>
          <asp:treenodebinding Depth="1" datamember="genre"
            textfield="name" valuefield="name"/>
          <asp:treenodebinding depth="2" datamember="book"
            textfield="title" valuefield="title"/>
          <asp:treenodebinding depth="3" datamember="chapter"
            textfield="name" valuefield="num"/>
        </databindings>
      </asp:treeview>

    </form>
  </BODY>
</HTML>

<%@ Page Language="VJ#" %>
<%@ Import Namespace="System.Xml.Xsl" %>


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<SCRIPT runat="server">
    private void TransformEventHandler(Object sender, System.EventArgs e)
    {
        // Add a dynamic transformation argument.
        System.DateTime.get_Now().AddDays(20);
    
        // Create an XsltArgumentList.
        XsltArgumentList xslArg = new XsltArgumentList();
        xslArg.AddParam("purchdate", "", System.DateTime.get_Now().AddDays(20).
            ToShortDateString());
        ((XmlDataSource)sender).set_TransformArgumentList(xslArg);
    }//TransformEventHandler
</SCRIPT>

<HTML>
  <BODY>
    <form runat="server">
      <asp:XmlDataSource
        id="XmlDataSource1"
        runat="server"
        datafile="bookstore.xml"
        transformfile="bookswithdiscount.xsl"
        ontransforming="TransformEventHandler" />

        <!- TreeView uses hierachical data, so the
            XmlDataSource uses an XmlHierarchicalDataSourceView
            when a TreeView is bound to it. -->

      <asp:treeview
        id="TreeView1"
        runat="server"
        datasourceid="XmlDataSource1">
        <databindings>
          <asp:treenodebinding Depth="1" datamember="genre"
            textfield="name" valuefield="name"/>
          <asp:treenodebinding depth="2" datamember="book"
            textfield="title" valuefield="title"/>
          <asp:treenodebinding depth="3" datamember="chapter"
            textfield="name" valuefield="num"/>
        </databindings>
      </asp:treeview>

    </form>
  </BODY>
</HTML>

The XML file in the code example has the following data:

<bookstore>
   <genre name="fiction">
     <book ISBN="0000000000">
       <title>Secrets of Silicon Valley</title>
       <price>12.95</price>
       <chapters>
         <chapter num="1" name="Introduction" />           
         <chapter num="2" name="Body" />          
         <chapter num="3" name="Conclusion" />
       </chapters>
     </book>
   </genre>
   <genre name="novel">
     <book genre="novel" ISBN="1111111111">
       <title>Straight Talk About Computers</title>
       <price>24.95</price>
       <chapters>
         <chapter num="1" name="Introduction" /> 
         <chapter num="2" name="Body" />
         <chapter num="3" name="Conclusion" />
       </chapters>
     </book>
   </genre>
</bookstore>

The XML transformation is performed using the following style sheet.

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:param name="purchdate"/>
 <xsl:template match="bookstore">
   <bookstore>
     <xsl:apply-templates select="genre"/>
   </bookstore>
 </xsl:template>
 <xsl:template match="genre">
   <genre>
     <xsl:attribute name="name">
       <xsl:value-of select="@name"/>
     </xsl:attribute>
     <xsl:apply-templates select="book"/>
   </genre>
 </xsl:template>
 <xsl:template match="book">
   <book>
     <xsl:attribute name="ISBN">
       <xsl:value-of select="@ISBN"/>
     </xsl:attribute>
     <xsl:attribute name="title">
       <xsl:value-of select="title"/>
       Price: <xsl:value-of select="price"/>
           15% discount if purchased by: <xsl:value-of select="$purchdate"/>      
     </xsl:attribute>
     <xsl:apply-templates select="chapters/chapter" />
   </book>
 </xsl:template>
 <xsl:template match="chapter">
   <chapter>
     <xsl:attribute name="num">
       <xsl:value-of select="@num"/>
     </xsl:attribute>
     <xsl:attribute name="name">
       <xsl:value-of select="@name"/>
     </xsl:attribute>
     <xsl:apply-templates/>
   </chapter>
 </xsl:template>
</xsl:stylesheet>

Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0

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