Need help hooking up XML file to WPF DataGrid

Here's what I've done so far:

1. In my App class, I declare a new XmlDataProvider and set the source to a valid XML file (whose Build Action is set to Content/Copy Always).

   public partial class App : Application
   {
       public App()
       {
           InitializeComponent();
           var services = new XmlDataProvider();
           services.Source = new Uri("pack://siteoforigin:,,,/Data/Services.xml"); // also tried an absolute path, but that made no difference
           var mainWindow = new MainWindow();
           mainWindow.DataContext = new MainViewModel(services);
           mainWindow.Show();
       }
   }
   

2. The XmlDataProvider gets passed into the ViewModel and gets assigned to the Services property.

3. I bind to the data like this:

   <mwc:DataGrid
       ItemsSource="{Binding Services, XPath=//Services/*}">
       <mwc:DataGrid.Columns>
           <mwc:DataGridTextColumn
               Binding="{Binding XPath=@name}"
               Header="Name" />
           <mwc:DataGridTextColumn ... />
           ...
       </mwc:DataGrid.Columns>
   </mwc:DataGrid>
   

The result:

The column headings of my DataGrid show up, but there are no rows of data. It compiles and runs without any errors, but if I check my Output window, I see this:

BindingExpression with XPath cannot bind to non-XML object.;
XPath='//Services/开发者_运维问答*'
BindingExpression:Path=Services;

Can the XmlDataProvider only be used declaratively?

If I attempt to create the XmlDataProvider declaratively in a ResourceDictionary like this...

<XmlDataProvider
    x:Key="Main_Services">
    <x:XData>
        <Services
            xmlns="">
            <Service
                name="Test"
                ... />
            <Service ... />
            ...
        </Services>
    </x:XData>
</XmlDataProvider>

...everything works fine (I get the expected rows in my DataGrid). (Note that I just pasted the contents of the XML file between the <x:XData> tags.)

If I try to set the Source via C#, however, there doesn't seem to be any data in the XmlDataProvider (literally, the Data property is null).

It doesn't seem to make any difference whether I use a "pack URI" or an absolute path when I assign the Source. I get no rows either way. I also tried calling the InitialLoad() method after setting the source, but that made no difference either.

Questions:

• Is XmlDataProvider just the wrong tool for the job or am I doing something wrong?
• Can XmlDataProvider only be used declaratively?
• I know there is XDocument and XmlDocument...should I be using one of those?

Declarative seems to be the way to go. This code works:

<XmlDataProvider
    x:Key="Main_Services"
    Source="pack://siteoforigin:,,,/Data/Services.xml">
</XmlDataProvider>

I have no idea why doing the same exact thing in C# fails, but I can live with this solution.