Consider the following scenario:

I want to bind the TextElement.FontWeight property to an xml attribute. The xml looks somewhat like this and has arbitrary depth.

<text font-weight="bold">
    bold text here
    <inlinetext>more bold text</inlinetext>
    even more bold text
</text>

I use hierarchical templating to display the text, no problem there, but having a Setter in the template style like:

<Setter Property="TextElement.FontWeight" Value="{Binding XPath=@font-weight}"/>

sets the fontweight correctly on the first level, but overwrites the second level with null (as the binding can't find the xpath) which reverts to Fontweight normal.

I tried all sorts of things here but nothing quite seems to work.

e.g. i used a converter to return UnsetValue, which didn't work.

I'm currently trying with:

<Setter Property="custom:AttributeInserter.Wrapper" Value="{custom:AttributeInserter Property=TextElement.FontWeight, Binding={Binding XPath=@font-weight}}"/>

Codebehind:

public static class AttributeInserter
{
    public static AttributeInserterExtension GetWrapper(DependencyObject obj)
    {
        return (AttributeInserterExtension)obj.GetValue(WrapperProperty);
    }
    public static void SetWrapper(DependencyObject obj, AttributeInserterExtension value)
    {
        obj.SetValue(WrapperProperty, value);
    }
    // Using a DependencyProperty as the backing store for Wrapper.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty WrapperProperty =
        DependencyProperty.RegisterAttached("Wrapper", typeof(AttributeInserterExtension), typeof(AttributeInserter), new UIPropertyMetadata(pcc));

    static void pcc(DependencyObject o,DependencyPropertyChangedEventArgs e)
    {
        var n=e.NewValue as AttributeInserterExtension;
        var c = o as FrameworkElement;
        if (n == null || c==null || n.Property==null || n.Binding==null)
            return;

        var bex = c.SetBinding(n.Property, n.Binding);
        bex.UpdateTarget();
        if (bex.Status == BindingStatus.UpdateTargetError)
            c.ClearValue(n.Property);
    }

}

public class AttributeInserterExtension : MarkupExtension
{
    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        return this;
    }

    public DependencyProperty Property { get; set; }
    public Binding Binding { get; set; }
}

which kinda works, but can't track changes of the property

Any ideas? Any links?

thx for the help