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Answer 1

A:

I'd just set up an attached property for this and create the logic you want in there. Then you would decorate your treeview with the attached property. We do something similar with other controls that contain scrollviewers:

public class ScrollResetService
{
    public static DependencyProperty IsScrollResetProperty = DependencyProperty.RegisterAttached("IsScrollReset",
                                                                                                 typeof(bool),
                                                                                                 typeof(ScrollResetService),
                                                                                                 new PropertyMetadata(false,
                                                                                                      OnIsScrollResetChanged));
    public static void SetIsScrollReset(DependencyObject d, bool value)
    {
        d.SetValue(IsScrollResetProperty, value);
    }

    public static bool GetIsScrollReset(DependencyObject d)
    {
        return d.GetValue(IsScrollResetProperty) == null ? false : (bool)d.GetValue(IsScrollResetProperty);
    }

    private static void OnIsScrollResetChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var treeView = d as TreeView;
        bool isScrollReset;
        if (e.NewValue!= null && bool.TryParse(e.NewValue.ToString(), out isScrollReset) && treeView != null)
        {

            treeView.SelectedItemChanged += (sender, args) =>
                                               {
                                                   var scrolls =
                                                       treeView.GetAllLogicalChildrenOfType<IScrollInfo>();
                                                   scrolls.ForEach(i => i.SetVerticalOffset(0));
                                               };

        }
    }

}

public static class Extensions
    {

public static IEnumerable<T> GetAllLogicalChildrenOfType<T>(this FrameworkElement parent)
        {
            Debug.Assert(parent != null, "The parent cannot be null.");
            return parent.GetVisualChildren().Flatten(item => item.GetVisualChildren()).OfType<T>();
        }

public static IEnumerable<T> Flatten<T>(this IEnumerable<T> items, Func<T, IEnumerable<T>> childSelector)
        {
            if (items == null) return Enumerable.Empty<T>();
            return items.Concat(items.SelectMany(i => childSelector(i).Flatten(childSelector)));
        }

internal static IEnumerable<DependencyObject> GetVisualChildren(this DependencyObject parent)
        {
            int childCount = VisualTreeHelper.GetChildrenCount(parent);
            for (int counter = 0; counter < childCount; counter++)
            {
                yield return VisualTreeHelper.GetChild(parent, counter);
            }
        }
}

Justice 2010-08-03 19:42:38

Sorry, sounds like that could work, but you're going to have to help me a little more.Could you show how I use those? Thanks, if this works I owe you my life!

JGord 2010-08-03 19:49:11

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Silverlight TreeView ScrollViewer Issue

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