using System;
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using System.Windows;
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using System.Windows.Controls;
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using System.Windows.Media.Animation;
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namespace HMI.UI
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{
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public class ScrollLabel : Control
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{
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static ScrollLabel()
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{
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DefaultStyleKeyProperty.OverrideMetadata(typeof(ScrollLabel), new FrameworkPropertyMetadata(typeof(ScrollLabel)));
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}
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private DoubleAnimation animation;
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public override void OnApplyTemplate()
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{
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base.OnApplyTemplate();
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// 在模板应用后启动初始动画
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var scrollViewer = GetTemplateChild("slv") as ScrollViewer;
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var label = GetTemplateChild("label") as Label;
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if (scrollViewer != null)
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{
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// 等待布局完成后再启动动画
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scrollViewer.Loaded += (s, e) =>
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{
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var storyboard = new Storyboard();
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animation = new DoubleAnimation
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{
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From = 0,
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To = scrollViewer.ScrollableWidth,
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Duration = new Duration(TimeSpan.FromSeconds(3)),
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AutoReverse = true,
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RepeatBehavior = RepeatBehavior.Forever,
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BeginTime = TimeSpan.FromSeconds(0.2)
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};
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Storyboard.SetTarget(animation, scrollViewer);
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Storyboard.SetTargetProperty(animation, new PropertyPath(ScrollViewerBehavior.HorizontalOffsetProperty));
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storyboard.Children.Add(animation);
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scrollViewer.Resources["ScrollAnimation"] = storyboard;
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storyboard.Begin();
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};
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}
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}
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private void ScrollViewer_ScrollChanged(object sender, ScrollChangedEventArgs e)
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{
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//RefreshAnimation();
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}
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private void RefreshAnimation()
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{
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// 查找ScrollViewer并重新启动动画
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var scrollViewer = GetTemplateChild("slv") as ScrollViewer;
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if (scrollViewer != null)
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{
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scrollViewer.Dispatcher.BeginInvoke(new Action(() =>
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{
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// 停止当前动画
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var storyboard = scrollViewer.Resources["ScrollAnimation"] as Storyboard;
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if (storyboard != null)
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{
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storyboard.Stop();
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if (animation != null)
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{
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animation.To = scrollViewer.ScrollableWidth;
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}
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storyboard.Begin();
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}
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}), System.Windows.Threading.DispatcherPriority.Background);
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}
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}
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public static readonly DependencyProperty ValueProperty =
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DependencyProperty.RegisterAttached("Value", typeof(string), typeof(ScrollLabel),
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new FrameworkPropertyMetadata(null, new PropertyChangedCallback(OnValueChanged)));
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private static void OnValueChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
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{
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var scrollLabel = obj as ScrollLabel;
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scrollLabel?.RefreshAnimation();
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}
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public event EventHandler<string> ValueChanged;
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public string Value
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{
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get { return (string)GetValue(ValueProperty); }
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set
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{
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SetValue(ValueProperty, value);
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}
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}
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}
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public static class ScrollViewerBehavior
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{
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public static readonly DependencyProperty HorizontalOffsetProperty =
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DependencyProperty.RegisterAttached("HorizontalOffset", typeof(double), typeof(ScrollViewerBehavior),
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new UIPropertyMetadata(0.0, OnHorizontalOffsetChanged));
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public static void SetHorizontalOffset(FrameworkElement target, double value)
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{
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target.SetValue(HorizontalOffsetProperty, value);
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}
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public static double GetHorizontalOffset(FrameworkElement target)
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{
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return (double)target.GetValue(HorizontalOffsetProperty);
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}
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private static void OnHorizontalOffsetChanged(DependencyObject target, DependencyPropertyChangedEventArgs e)
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{
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var view = target as ScrollViewer;
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if (view != null)
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{
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view.ScrollToHorizontalOffset((double)e.NewValue);
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}
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}
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public static readonly DependencyProperty VerticalOffsetProperty = DependencyProperty.RegisterAttached("VerticalOffset", typeof(double), typeof(ScrollViewerBehavior), new UIPropertyMetadata(0.0, OnVerticalOffsetChanged));
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public static void SetVerticalOffset(FrameworkElement target, double value)
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{
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target.SetValue(VerticalOffsetProperty, value);
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}
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public static double GetVerticalOffset(FrameworkElement target)
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{
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return (double)target.GetValue(VerticalOffsetProperty);
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}
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private static void OnVerticalOffsetChanged(DependencyObject target, DependencyPropertyChangedEventArgs e)
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{
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var view = target as ScrollViewer;
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if (view != null)
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{
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view.ScrollToVerticalOffset((double)e.NewValue);
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}
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}
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}
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}
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