XmlDataSource.Transforming Event
Definition
Important
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Occurs before the style sheet that is defined by the Transform property or identified by the TransformFile property is applied to XML data.
public:
event EventHandler ^ Transforming;public event EventHandler Transforming;member this.Transforming : EventHandler Public Custom Event Transforming As EventHandler Event Type
Examples
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 at run time. 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.
<%@ 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 xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" 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="VB" %>
<%@ Import Namespace="System.Xml.Xsl" %>
<script runat="server">
Private Sub TransformEventHandler(sender As Object, e as EventArgs)
' Add a dynamic transformation argument.
Dim d As New DateTime
d = DateTime.Now.AddDays(20)
'Create an XsltArgumentList.
Dim xslArg As XsltArgumentList = New XsltArgumentList
xslArg.AddParam("purchdate", "", d.ToShortDateString())
Dim aXmlDataSource as XmlDataSource = CType(sender, XmlDataSource)
aXmlDataSource.TransformArgumentList = xslArg
End Sub ' TransformEventHandler
</script>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" 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 transformation of the XML data is performed with 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>
Remarks
Handle the Transforming event to set the TransformArgumentList property with an XsltArgumentList object before the XmlDataSource control performs an XML transformation.
For more information about how to handle events, see Handling and Raising Events.
