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using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media.Animation;
namespace Gestor.Common.Helpers
{
public static class ScrollAnimationBehavior
{
public static DependencyProperty VerticalOffsetProperty;
public static DependencyProperty TimeDurationProperty;
public static DependencyProperty PointsToScrollProperty;
public static DependencyProperty IsEnabledProperty;
private static double _currentToValue;
private static Storyboard _storyboard;
static ScrollAnimationBehavior()
{
ScrollAnimationBehavior.VerticalOffsetProperty = DependencyProperty.RegisterAttached("VerticalOffset", typeof(double), typeof(ScrollAnimationBehavior), new UIPropertyMetadata((object)0, new PropertyChangedCallback(ScrollAnimationBehavior.OnVerticalOffsetChanged)));
ScrollAnimationBehavior.TimeDurationProperty = DependencyProperty.RegisterAttached("TimeDuration", typeof(TimeSpan), typeof(ScrollAnimationBehavior), new PropertyMetadata((object)(new TimeSpan(0, 0, 0, 0, 0))));
ScrollAnimationBehavior.PointsToScrollProperty = DependencyProperty.RegisterAttached("PointsToScroll", typeof(double), typeof(ScrollAnimationBehavior), new PropertyMetadata((object)0));
ScrollAnimationBehavior.IsEnabledProperty = DependencyProperty.RegisterAttached("IsEnabled", typeof(bool), typeof(ScrollAnimationBehavior), new UIPropertyMetadata(false, new PropertyChangedCallback(ScrollAnimationBehavior.OnIsEnabledChanged)));
}
private static void AnimateScroll(ScrollViewer scrollViewer)
{
DoubleAnimationUsingKeyFrames doubleAnimationUsingKeyFrame = new DoubleAnimationUsingKeyFrames()
{
Duration = new Duration(ScrollAnimationBehavior.GetTimeDuration(scrollViewer))
};
doubleAnimationUsingKeyFrame.KeyFrames.Add(new EasingDoubleKeyFrame(scrollViewer.VerticalOffset, KeyTime.FromPercent(0)));
doubleAnimationUsingKeyFrame.KeyFrames.Add(new EasingDoubleKeyFrame(ScrollAnimationBehavior._currentToValue, KeyTime.FromPercent(1), new SineEase()
{
EasingMode = EasingMode.EaseOut
}));
ScrollAnimationBehavior._storyboard = new Storyboard();
ScrollAnimationBehavior._storyboard.Children.Add(doubleAnimationUsingKeyFrame);
Storyboard.SetTarget(doubleAnimationUsingKeyFrame, scrollViewer);
Storyboard.SetTargetProperty(doubleAnimationUsingKeyFrame, new PropertyPath(ScrollAnimationBehavior.VerticalOffsetProperty));
ScrollAnimationBehavior._storyboard.Begin();
}
public static TimeSpan GetTimeDuration(FrameworkElement target)
{
return (TimeSpan)target.GetValue(ScrollAnimationBehavior.TimeDurationProperty);
}
private static void OnIsEnabledChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
ScrollViewer scrollViewer = sender as ScrollViewer;
if (scrollViewer != null)
{
scrollViewer.Loaded += new RoutedEventHandler(ScrollAnimationBehavior.ScrollerLoaded);
}
}
private static void OnVerticalOffsetChanged(DependencyObject target, DependencyPropertyChangedEventArgs e)
{
ScrollViewer scrollViewer = target as ScrollViewer;
if (scrollViewer != null)
{
scrollViewer.ScrollToVerticalOffset((double)e.NewValue);
}
}
private static void ScrollerLoaded(object sender, RoutedEventArgs e)
{
ScrollAnimationBehavior.SetEventHandlersForScrollViewer(sender as ScrollViewer);
}
private static void ScrollViewerPreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
double num;
double num1 = ScrollAnimationBehavior._currentToValue;
double delta = (double)e.Delta;
ScrollViewer scrollViewer = (ScrollViewer)sender;
double num2 = delta * 2 / 3;
if (ScrollAnimationBehavior._storyboard == null || ScrollAnimationBehavior._storyboard.GetCurrentState() == ClockState.Filling)
{
ScrollAnimationBehavior._currentToValue = scrollViewer.VerticalOffset;
}
if (num2 > ScrollAnimationBehavior._currentToValue)
{
num = 0;
}
else
{
num = (ScrollAnimationBehavior._currentToValue - num2 > scrollViewer.ScrollableHeight ? scrollViewer.ScrollableHeight : ScrollAnimationBehavior._currentToValue - num2);
}
ScrollAnimationBehavior._currentToValue = num;
if (ScrollAnimationBehavior._currentToValue != scrollViewer.VerticalOffset && ScrollAnimationBehavior._currentToValue != num1)
{
ScrollAnimationBehavior.AnimateScroll(scrollViewer);
}
e.Handled = true;
}
private static void SetEventHandlersForScrollViewer(ScrollViewer scroller)
{
scroller.PreviewMouseWheel += new MouseWheelEventHandler(ScrollAnimationBehavior.ScrollViewerPreviewMouseWheel);
}
public static void SetIsEnabled(FrameworkElement target, bool value)
{
target.SetValue(ScrollAnimationBehavior.IsEnabledProperty, value);
}
public static void SetPointsToScroll(FrameworkElement target, double value)
{
target.SetValue(ScrollAnimationBehavior.PointsToScrollProperty, value);
}
public static void SetTimeDuration(FrameworkElement target, TimeSpan value)
{
target.SetValue(ScrollAnimationBehavior.TimeDurationProperty, value);
}
}
}
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