The current version of the Microsoft Live Labs PivotViewer control for SilverLight 4 has no way to style the elements of the control. Looking at the control in Reflector, I can see much of the style info is set in a ResourceDictionary in the assembly (assets/defaultcolors.xaml). What I would like to do is create my own copy of this file, then replace it at runtime on the PivotViewer control.
By subclassing the PivotViewer control and overriding OnApplyTemplate I can grab the child elements and set properties such as Background. I have not had any success Clear()'ng the MergedDictionaries and adding in my own:
public override void OnApplyTemplate() {
base.OnApplyTemplate();
/* can change things this way */
CollectionViewerView cvv = ((CollectionViewerView)((Grid)this.GetTemplateChild("PART_Container")).Children[0]);
((Grid)cvv.Content).Background = new SolidColorBrush(Colors.Black);
/* can't change things this way */
CustomDictionary gd = new CustomDictionary();
cvv.Resources.MergedDictionaries.Clear();
cvv.Resources.MergedDictionaries.Add(gd);
}