using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Media;
namespace YALV.Common
{
///
/// Refs: http://www.codeproject.com/Articles/39244/Scroll-Synchronization
///
public class ScrollSynchronizer : DependencyObject
{
///
/// Identifies the attached property ScrollGroup
///
public static readonly DependencyProperty ScrollGroupProperty =
DependencyProperty.RegisterAttached("ScrollGroup", typeof(string), typeof(ScrollSynchronizer), new PropertyMetadata(new PropertyChangedCallback(OnScrollGroupChanged)));
///
/// List of all registered scroll viewers.
///
private static Dictionary scrollViewers = new Dictionary();
#if SILVERLIGHT
///
/// List of all registered scrollbars.
///
private static Dictionary horizontalScrollBars = new Dictionary();
///
/// List of all registered scrollbars.
///
private static Dictionary verticalScrollBars = new Dictionary();
#endif
///
/// Contains the latest horizontal scroll offset for each scroll group.
///
private static Dictionary horizontalScrollOffsets = new Dictionary();
///
/// Contains the latest vertical scroll offset for each scroll group.
///
private static Dictionary verticalScrollOffsets = new Dictionary();
///
/// Sets the value of the attached property ScrollGroup.
///
/// Object on which the property should be applied.
/// Value of the property.
public static void SetScrollGroup(DependencyObject obj, string scrollGroup)
{
obj.SetValue(ScrollGroupProperty, scrollGroup);
}
///
/// Gets the value of the attached property ScrollGroup.
///
/// Object for which the property should be read.
/// Value of the property StartTime
public static string GetScrollGroup(DependencyObject obj)
{
return (string)obj.GetValue(ScrollGroupProperty);
}
///
/// Occurs, when the ScrollGroupProperty has changed.
///
/// The DependencyObject on which the property has changed value.
/// Event data that is issued by any event that tracks changes to the effective value of this property.
private static void OnScrollGroupChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var scrollViewer = d as ScrollViewer;
if (scrollViewer != null)
{
if (!string.IsNullOrEmpty((string)e.OldValue))
{
// Remove scrollviewer
if (scrollViewers.ContainsKey(scrollViewer))
{
#if SILVERLIGHT
horizontalScrollBars.Remove(horizontalScrollBars.First(s => s.Value == scrollViewer).Key);
verticalScrollBars.Remove(verticalScrollBars.First(s => s.Value == scrollViewer).Key);
scrollViewer.Loaded += new RoutedEventHandler(ScrollViewer_Loaded);
#else
scrollViewer.ScrollChanged -= new ScrollChangedEventHandler(ScrollViewer_ScrollChanged);
#endif
scrollViewers.Remove(scrollViewer);
}
}
if (!string.IsNullOrEmpty((string)e.NewValue))
{
// If group already exists, set scrollposition of new scrollviewer to the scrollposition of the group
if (horizontalScrollOffsets.Keys.Contains((string)e.NewValue))
{
scrollViewer.ScrollToHorizontalOffset(horizontalScrollOffsets[(string)e.NewValue]);
}
else
{
horizontalScrollOffsets.Add((string)e.NewValue, scrollViewer.HorizontalOffset);
}
if (verticalScrollOffsets.Keys.Contains((string)e.NewValue))
{
scrollViewer.ScrollToVerticalOffset(verticalScrollOffsets[(string)e.NewValue]);
}
else
{
verticalScrollOffsets.Add((string)e.NewValue, scrollViewer.VerticalOffset);
}
// Add scrollviewer
scrollViewers.Add(scrollViewer, (string)e.NewValue);
#if !SILVERLIGHT
scrollViewer.ScrollChanged += new ScrollChangedEventHandler(ScrollViewer_ScrollChanged);
#else
scrollViewer.Loaded += new RoutedEventHandler(ScrollViewer_Loaded);
#endif
}
}
}
#if !SILVERLIGHT
///
/// Occurs, when the scroll offset of one scrollviewer has changed.
///
/// The sender of the event.
/// EventArgs of the event.
private static void ScrollViewer_ScrollChanged(object sender, ScrollChangedEventArgs e)
{
var changedScrollViewer = sender as ScrollViewer;
if (e.VerticalChange != 0 && e.HorizontalChange != 0)
Scroll(changedScrollViewer, true, true);
else if (e.VerticalChange != 0)
Scroll(changedScrollViewer, true, false);
else if (e.HorizontalChange != 0)
Scroll(changedScrollViewer, false, true);
}
#endif
#if SILVERLIGHT
///
/// Occurs, when the scroll viewer is loaded.
///
/// The sender of the event.
/// EventArgs of the event.
private static void ScrollViewer_Loaded(object sender, RoutedEventArgs e)
{
var scrollViewer = (ScrollViewer)sender;
var group = scrollViewers[scrollViewer];
scrollViewer.Opacity = 1;
if (verticalScrollOffsets.Keys.Contains(group))
{
scrollViewer.ScrollToVerticalOffset(verticalScrollOffsets[group]);
}
scrollViewer.ApplyTemplate();
var scrollViewerRoot = (FrameworkElement)VisualTreeHelper.GetChild(scrollViewer, 0);
var horizontalScrollBar = (ScrollBar)scrollViewerRoot.FindName("HorizontalScrollBar");
var verticalScrollBar = (ScrollBar)scrollViewerRoot.FindName("VerticalScrollBar");
if (!horizontalScrollBars.Keys.Contains(horizontalScrollBar))
{
horizontalScrollBars.Add(horizontalScrollBar, scrollViewer);
}
if (!verticalScrollBars.Keys.Contains(verticalScrollBar))
{
verticalScrollBars.Add(verticalScrollBar, scrollViewer);
}
if (horizontalScrollBar != null)
{
horizontalScrollBar.Scroll += new ScrollEventHandler(HorizontalScrollBar_Scroll);
horizontalScrollBar.ValueChanged += new RoutedPropertyChangedEventHandler(HorizontalScrollBar_ValueChanged);
}
if (verticalScrollBar != null)
{
verticalScrollBar.Scroll += new ScrollEventHandler(VerticalScrollBar_Scroll);
verticalScrollBar.ValueChanged += new RoutedPropertyChangedEventHandler(VerticalScrollBar_ValueChanged);
}
}
///
/// Occurs, when the horizontal scroll bar was moved.
///
/// The sender of the event.
/// EventArgs of the event.
private static void HorizontalScrollBar_ValueChanged(object sender, RoutedPropertyChangedEventArgs e)
{
var changedScrollBar = sender as ScrollBar;
var changedScrollViewer = horizontalScrollBars[changedScrollBar];
Scroll(changedScrollViewer, false, true);
}
///
/// Occurs, when the vertical scroll bar was moved.
///
/// The sender of the event.
/// EventArgs of the event.
private static void VerticalScrollBar_ValueChanged(object sender, RoutedPropertyChangedEventArgs e)
{
var changedScrollBar = sender as ScrollBar;
var changedScrollViewer = verticalScrollBars[changedScrollBar];
Scroll(changedScrollViewer, true, false);
}
///
/// Occurs, when the horizontal scroll bar was moved.
///
/// The sender of the event.
/// EventArgs of the event.
private static void HorizontalScrollBar_Scroll(object sender, ScrollEventArgs e)
{
var changedScrollBar = sender as ScrollBar;
var changedScrollViewer = horizontalScrollBars[changedScrollBar];
Scroll(changedScrollViewer, false, true);
}
///
/// Occurs, when the vertical scroll bar was moved.
///
/// The sender of the event.
/// EventArgs of the event.
private static void VerticalScrollBar_Scroll(object sender, ScrollEventArgs e)
{
var changedScrollBar = sender as ScrollBar;
var changedScrollViewer = verticalScrollBars[changedScrollBar];
Scroll(changedScrollViewer, true, false);
}
#endif
///
/// Scrolls all scroll viewers of a group to the position of the selected scroll viewer.
///
/// Sroll viewer, that specifies the current position of the group.
private static void Scroll(ScrollViewer changedScrollViewer, bool verticalChange, bool horizontalChange)
{
var group = scrollViewers[changedScrollViewer];
verticalScrollOffsets[group] = changedScrollViewer.VerticalOffset;
horizontalScrollOffsets[group] = changedScrollViewer.HorizontalOffset;
foreach (var scrollViewer in scrollViewers.Where((s) => s.Value == group && s.Key != changedScrollViewer))
{
if (verticalChange && scrollViewer.Key.VerticalOffset != changedScrollViewer.VerticalOffset)
{
scrollViewer.Key.ScrollToVerticalOffset(changedScrollViewer.VerticalOffset);
}
if (horizontalChange && scrollViewer.Key.HorizontalOffset != changedScrollViewer.HorizontalOffset)
{
scrollViewer.Key.ScrollToHorizontalOffset(changedScrollViewer.HorizontalOffset);
}
}
}
}
}