How to load XML into C# WPF treeview

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To answer your question, you should be binding your XmlDocument to the ListView's ItemsSource property like this:

XmlDocument d = new XmlDocument();
d.Load(@"C:\Users\Anton\Desktop\plglst.xml");

var binding = new Binding();
binding.Source = d.DocumentElement;
theListView.SetBinding(ListView.ItemsSourceProperty, binding);

Then in your XAML you declare GridViewCollumns for the attributes you want to display:

<ListView x:Name="theListView">
    <ListView.View>
        <GridView>
            <GridViewColumn Header="CLSID" DisplayMemberBinding="{Binding XPath=@CLSID}"/>
            <GridViewColumn Header="Category" DisplayMemberBinding="{Binding XPath=@Category}"/>
            <GridViewColumn Header="Name" DisplayMemberBinding="{Binding XPath=@Name}"/>
            <GridViewColumn Header="Original Name" DisplayMemberBinding="{Binding XPath=@OriginalName}"/>
        </GridView>
    </ListView.View>
</ListView>

Result:

To be honest though I would recommend against binding directly to an XmlDocument like this. XML is designed to encode documents, once you've actually loaded the data off disk there's really little to be gained by keeping it in that format and sooner or later it'll just wind up getting in the way. A better solution is to create an intermediate data-structure which you can decorate with attributes to show how the XML schema maps the data:

public class Plugin
{
    [XmlAttribute("CLSID")]
    public string CLSID { get; set; }

    [XmlAttribute("Category")]
    public string Category { get; set; }

    [XmlAttribute("Name")]
    public string Name { get; set; }

    [XmlAttribute("OriginalName")]
    public string OriginalName { get; set; }
}

Your load code now deseralizes directly into an array of type Plugin and assigns it to your ListView's ItemsSource directly:

var serializer = new XmlSerializer(typeof(Plugin[]), new XmlRootAttribute { ElementName = "PluginMenuLayout" });
using (XmlReader reader = XmlReader.Create(@"C:\Users\Anton\Desktop\plglst.xml"))
    theListView.ItemsSource = serializer.Deserialize(reader) as Plugin[];

A slight modification to your ListView column bindings and you're done:

<ListView x:Name="theListView">
    <ListView.View>
        <GridView>
            <GridViewColumn Header="CLSID" DisplayMemberBinding="{Binding CLSID}"/>
            <GridViewColumn Header="Category" DisplayMemberBinding="{Binding Category}"/>
            <GridViewColumn Header="Name" DisplayMemberBinding="{Binding Name}"/>
            <GridViewColumn Header="Original Name" DisplayMemberBinding="{Binding OriginalName}"/>
        </GridView>
    </ListView.View>
</ListView>