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chrisnicola / TreeViewItemFinder.cs

Created 2010-12-26

using System;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Threading;
 
namespace Presentation.Helpers {
 
	public static class TreeViewitemFinder {
		public static TreeViewItem BringTreeViewItemIntoView(this TreeView treeView, TreeViewItemModel item) {
			if (item == null) return null;
			ItemsControl parentContainer = (ItemsControl) treeView.BringTreeViewItemIntoView(item.Parent) ?? treeView;
			return parentContainer.BringItemIntoView(item);
		}
 
		private static TreeViewItem BringItemIntoView(this ItemsControl container, object item) {
			var vsp = container.FindVisualChild<MyVirtualizingStackPanel>();
			if (vsp == null) {
				var treeViewItem = (TreeViewItem) container.ItemContainerGenerator.ContainerFromItem(item);
				treeViewItem.BringIntoView();
				return treeViewItem;
			}
			//Use exposed BringIntoView method to render each of the items in order
			for (int i = 0; i < container.Items.Count; i++) {
				vsp.Dispatcher.Invoke(DispatcherPriority.ContextIdle, (Action<int>) vsp.BringIntoView, i);
				var nextitem = (TreeViewItem) container.ItemContainerGenerator.ContainerFromIndex(i);
				if (nextitem.DataContext == item) {
					nextitem.Dispatcher.Invoke(DispatcherPriority.ContextIdle, (Action) nextitem.BringIntoView);
					return nextitem;
				}
			}
			return null;
		}
 
		private static T FindVisualChild<T>(this Visual visual) where T : Visual {
			for (int i = 0; i < VisualTreeHelper.GetChildrenCount(visual); i++) {
				var child = (Visual) VisualTreeHelper.GetChild(visual, i);
				if (child != null) {
					var correctlyTyped = child as T;
					if (correctlyTyped != null)
						return correctlyTyped;
					var descendent = FindVisualChild<T>(child);
					if (descendent != null)
						return descendent;
				}
			}
			return null;
		}
	}
 
	public class MyVirtualizingStackPanel : VirtualizingStackPanel {
		public void BringIntoView(int index) { BringIndexIntoView(index); }
	}
}