XmlDataProvider and XPath bindings don't allow default namespace of XML data? - xaml

Question

I am struggling to work out how to use default namespaces with XmlDataProvider and XPath bindings.
There's an ugly answer using local-name <Binding XPath="*[local-name()='Name']" /> but that is not acceptable to the client who wants this XAML to be highly maintainable.
The fallback is to force them to use non-default namespaces in the report XML but that is an undesirable solution.
The XML report file looks like the following. It will only work if I remove xmlns="http://www.acme.com/xml/schemas/report so there is no default namespace.
<?xml version="1.0" encoding="utf-8"?>
<?xml-stylesheet type='text/xsl' href='PreviewReportImages.xsl'?>
<Report xsl:schemaLocation="http://www.acme.com/xml/schemas/report BlahReport.xsd" xmlns:xsl="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.acme.com/xml/schemas/report">
<Service>Muncher</Service>
<Analysis>
<Date>27 Apr 2010</Date>
<Time>0:09</Time>
<Authoriser>Service Centre Manager</Authoriser>
Which I am presenting in a window with XAML:
<Window x:Class="AcmeTest.ReportPreview"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="ReportPreview" Height="300" Width="300" >
<Window.Resources>
<XmlDataProvider x:Key="Data"/>
</Window.Resources>
<StackPanel Orientation="Vertical" DataContext="{Binding Source={StaticResource Data}, XPath=Report}">
<TextBlock Text="{Binding XPath=Service}"/>
</StackPanel>
</Window>
with code-behind used to load an XmlDocument into the XmlDataProvider (seems the only way to have loading from a file or object varying at runtime).
public partial class ReportPreview : Window
{
private void InitXmlProvider(XmlDocument doc)
{
XmlDataProvider xd = (XmlDataProvider)Resources["Data"];
xd.Document = doc;
}
public ReportPreview(XmlDocument doc)
{
InitializeComponent();
InitXmlProvider(doc);
}
public ReportPreview(String reportPath)
{
InitializeComponent();
var doc = new XmlDocument();
doc.Load(reportPath);
InitXmlProvider(doc);
}
}

Answer 1

I hadn't realised that I don't need to add a prefix to the client XML data, just use a prefix in my XPath expressions that maps to the same URI as the default namespace (obvious when I slept on it!).
So, the fix was to add a namespace mapping as shown here, note the use of the r: prefix on the elements.
<Window x:Class="AcmeTest.ReportPreview"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="ReportPreview" Height="300" Width="300" >
<Window.Resources>
<XmlDataProvider x:Key="Data">
<XmlDataProvider.XmlNamespaceManager>
<XmlNamespaceMappingCollection>
<XmlNamespaceMapping
Uri="http://www.acme.com/xml/schemas/report"
Prefix="r" />
</XmlNamespaceMappingCollection>
</XmlDataProvider.XmlNamespaceManager>
</XmlDataProvider>
</Window.Resources>
<StackPanel Orientation="Vertical" DataContext="{Binding Source={StaticResource Data}, XPath=Report}">
<TextBlock Text="{Binding XPath=r:Service}"/>
<TextBlock Text=" "/>
<TextBlock Text="{Binding XPath=r:Name/r:Last}"/>
</StackPanel>
</Window>