"Lawrence Oluyede" <ra***@dot.com> wrote in message news:rr*****************************@40tude.net...
Is there a way to treat html tags like simple text?
Put them in CDATA sections?
: : the XPathNavigator.Value obiously returns "I have 3 accounts blah blah", is
there a way to have all the inner stuff as text if the navigator is
positioned on the <content> tag? Like
"<div xmlns="http://www.w3.org/1999/xhtml">I have 3 accounts to give away,
let me know if you want them</div>"
Like the InnerXml property?
It's strange (and XPath doesn't provide such feature AFAIK) but it could be
useful
It's difficult (sometimes nearly impossible) to match and manipulate arbitrary mixed
content with XPath, although I think you're referring to the XPathNavigator class.
Of course, there's nothing to prevent you from walking the navigator and serializing
it directly (a healthy aversion to angle brackets aside). Here's a class I created that
encapsulates walking a navigator:
- - - XPathWalker.cs
using System;
using System.IO;
using System.Xml;
using System.Xml.XPath;
class NavigateEventArgs : EventArgs
{
public string NamespaceURI;
public string LocalName;
public string Prefix;
public string Value;
public NavigateEventArgs( string prefix, string localName, string nsUri, string valueStr)
{
this.Prefix = prefix;
this.LocalName = localName;
this.NamespaceURI = nsUri;
this.Value = valueStr;
}
}
class CompleteEventArgs : EventArgs
{
}
delegate bool MoveFirstDelegate( );
delegate bool MoveNextDelegate( );
delegate void NavigateEventHandler( object sender, NavigateEventArgs args);
delegate void CompleteEventHandler( object sender, CompleteEventArgs args);
internal class AxisWalker
{
private enum Status
{
Initial = 0, NoContent = 1, Active = 2
}
private MoveFirstDelegate moveFirst;
private MoveNextDelegate moveNext;
private AxisWalker.Status walkState;
protected XPathNavigator navigator;
public bool IsEmpty;
public event NavigateEventHandler Navigate;
public event CompleteEventHandler Complete;
public AxisWalker( MoveFirstDelegate firstFunc, MoveNextDelegate nextFunc)
{
this.navigator = firstFunc.Target as XPathNavigator;
this.moveFirst = firstFunc;
this.moveNext = nextFunc;
this.walkState = Status.Initial;
}
protected virtual void OnNavigate( NavigateEventArgs args)
{
if ( null != this.Navigate )
this.Navigate( this, args);
}
protected virtual void OnComplete( CompleteEventArgs args)
{
if ( null != this.Complete )
this.Complete( this, args);
}
public bool Step( )
{
if ( this.walkState == Status.Initial )
{
if ( this.moveFirst( ) )
{
this.walkState = Status.Active;
this.OnNavigate(
new NavigateEventArgs(
this.navigator.Prefix,
this.navigator.LocalName,
this.navigator.NamespaceURI,
this.navigator.ToString( )
)
);
}
else
{
this.IsEmpty = true;
this.walkState = Status.NoContent;
this.OnComplete( new CompleteEventArgs( ));
}
}
else
{
if ( this.moveNext() )
{
this.OnNavigate(
new NavigateEventArgs(
this.navigator.Prefix,
this.navigator.LocalName,
this.navigator.NamespaceURI,
this.navigator.ToString( )
)
);
}
else
{
this.walkState = Status.NoContent;
this.OnComplete( new CompleteEventArgs( ));
}
}
return ( this.walkState != Status.NoContent );
}
public void Walk( )
{
while ( this.Step( ) )
{
;
}
}
public void Reset()
{
this.walkState = Status.Initial;
this.IsEmpty = false;
}
}
internal class NamespaceAxisWalker : AxisWalker
{
public NamespaceAxisWalker( MoveFirstDelegate firstFunc, MoveNextDelegate nextFunc) : base( firstFunc, nextFunc) { ; }
protected override void OnNavigate( NavigateEventArgs args)
{
// There will be xml xmlns namespace decls on each element, although
// for most purposes, they are unnecessary in the serialization, so I
// discard them with this if-statement.
//
if ( "xml" != this.navigator.Name )
{
// Rearrange the arguments b/c Namespace axis has 'prefix' in .Name property,
// and .NamespaceURI in it's text value representation.
//
base.OnNavigate(
new NavigateEventArgs(
this.navigator.Name,
String.Empty,
args.Value,
String.Empty
)
);
}
}
}
public class XPathWalker
{
private AxisWalker elementWalker;
private AxisWalker attributeWalker;
private NamespaceAxisWalker nsWalker;
private XPathNavigator navigator;
private TextWriter sink;
public XPathWalker( XPathNavigator nav, TextWriter writer)
{
navigator = nav;
sink = writer;
elementWalker = new AxisWalker(
new MoveFirstDelegate( navigator.MoveToFirstChild),
new MoveNextDelegate( navigator.MoveToNext)
);
attributeWalker = new AxisWalker(
new MoveFirstDelegate( navigator.MoveToFirstAttribute),
new MoveNextDelegate( navigator.MoveToNextAttribute)
);
nsWalker = new NamespaceAxisWalker(
new MoveFirstDelegate( navigator.MoveToFirstNamespace),
new MoveNextDelegate( navigator.MoveToNextNamespace)
);
elementWalker.Navigate += new NavigateEventHandler( this.NavigateElement);
elementWalker.Complete += new CompleteEventHandler( this.CompleteElement);
nsWalker.Navigate += new NavigateEventHandler( this.NavigateNamespace);
nsWalker.Complete += new CompleteEventHandler( this.CompleteNamespace);
attributeWalker.Navigate += new NavigateEventHandler( this.NavigateAttribute);
attributeWalker.Complete += new CompleteEventHandler( this.CompleteAttribute);
}
public void Walk( )
{
navigator.MoveToParent( );
elementWalker.Walk( );
}
private void NavigateElement( object sender, NavigateEventArgs args)
{
if ( navigator.NodeType == XPathNodeType.Element )
{
string tag = (args.Prefix.Length > 0) ?
String.Format( "{0}:{1}", args.Prefix, args.LocalName) :
args.LocalName;
sink.Write( String.Format( "<{0}", tag));
nsWalker.Reset( );
nsWalker.Walk( );
attributeWalker.Reset( );
attributeWalker.Walk( );
sink.Write( '>');
AxisWalker childWalker = new AxisWalker(
new MoveFirstDelegate( navigator.MoveToFirstChild),
new MoveNextDelegate( navigator.MoveToNext)
);
childWalker.Navigate += new NavigateEventHandler( this.NavigateElement);
childWalker.Complete += new CompleteEventHandler( this.CompleteElement);
childWalker.Walk( );
sink.Write( "</{0}>", tag);
}
else if ( navigator.NodeType == XPathNodeType.Text )
{
sink.Write( args.Value);
}
}
private void NavigateNamespace( object sender, NavigateEventArgs args)
{
string ns = (args.Prefix.Length > 0) ?
String.Format( " xmlns:{0}='{1}'", args.Prefix, args.NamespaceURI) :
String.Format( " xmlns='{0}'", args.NamespaceURI);
sink.Write( ns);
}
private void NavigateAttribute( object sender, NavigateEventArgs args)
{
string attr = (args.Prefix.Length > 0) ?
String.Format( " {0}:{1}='{2}'", args.Prefix, args.LocalName, args.Value) :
String.Format( " {0}='{1}'", args.LocalName, args.Value);
sink.Write( attr);
}
private void CompleteElement( object sender, CompleteEventArgs args)
{
if ( !(sender as AxisWalker).IsEmpty )
navigator.MoveToParent( );
}
private void CompleteNamespace( object sender, CompleteEventArgs args)
{
if ( !(sender as AxisWalker).IsEmpty )
navigator.MoveToParent( );
}
private void CompleteAttribute( object sender, CompleteEventArgs args)
{
if ( !(sender as AxisWalker).IsEmpty )
navigator.MoveToParent( );
}
}
- - -
It's easy to walk any XPathNavigator instance with this class (positioned on any top-level context node).
The following two lines of code will emit an XmlDocument to the Console output:
XPathWalker goForA = new XPathWalker( doc.CreateNavigator( ), Console.Out);
goForA.Walk( );
That said, there's yet another method to generate serialized output from an XPathNavigator. Hand it to
an XslTransform that performs an identity transformation. As you're undoubtedly aware, XslTransform
can feed the proceeds of the transformation into any TextWriter, which is easily redirected into any old
StringWriter.
Here are three lines of code that can achieve comparable results to the XPathWalker above:
XslTransform xf = new XslTransform( );
xf.Load( "Identity.xsl");
xf.Transform( doc.CreateNavigator( ), null, Console.Out);
Now, you do need a copy of the ubiquitous Identity stylesheet to run that C# code, so here it is:
- - - Identity.xsl
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="no"/>
<xsl:template match="@*|node()">
<xsl:copy>
<xsl:apply-templates select="@*|node()"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
- - -
So, there's two ways to get serialize into text the inner content of the XPathNavigator. Good luck.
Derek Harmon
