Synchronize the Net40

Net40/HandyControl_Net40/Controls/Other/GotoTop.cs

@@ -0,0 +1,100 @@
+using System;
+using System.Windows;
+using System.Windows.Controls;
+using HandyControl.Data;
+using HandyControl.Tools;
+using HandyControl.Tools.Extension;
+
+namespace HandyControl.Controls
+{
+    public class GotoTop : Button
+    {
+        private Action _gotoTopAction;
+
+        private System.Windows.Controls.ScrollViewer _scrollViewer;
+
+        public static readonly DependencyProperty TargetProperty = DependencyProperty.Register(
+            "Target", typeof(DependencyObject), typeof(GotoTop), new PropertyMetadata(default(DependencyObject)));
+
+        public DependencyObject Target
+        {
+            get => (DependencyObject)GetValue(TargetProperty);
+            set => SetValue(TargetProperty, value);
+        }
+
+        public GotoTop() => Loaded += (s, e) => CreateGotoAction(Target);
+
+        public virtual void CreateGotoAction(DependencyObject obj)
+        {
+            if (_scrollViewer != null)
+            {
+                _scrollViewer.ScrollChanged -= ScrollViewer_ScrollChanged;
+            }
+            _scrollViewer = VisualHelper.GetGetChild<System.Windows.Controls.ScrollViewer>(obj);
+            if (_scrollViewer != null)
+            {
+                _scrollViewer.ScrollChanged += ScrollViewer_ScrollChanged;
+
+                if (_scrollViewer is ScrollViewer scrollViewerHandy && Animated && scrollViewerHandy.IsEnableInertia)
+                {
+                    _gotoTopAction = () => scrollViewerHandy.ScrollToTopInternal(AnimationTime);
+                }
+                else
+                {
+                    _gotoTopAction = () => _scrollViewer.ScrollToTop();
+                }
+            }
+        }
+
+        private void ScrollViewer_ScrollChanged(object sender, ScrollChangedEventArgs e)
+        {
+            if (AutoHiding)
+            {
+                this.Show(e.VerticalOffset >= HidingHeight);
+            }
+        }
+
+        public static readonly DependencyProperty AnimatedProperty = DependencyProperty.Register(
+            "Animated", typeof(bool), typeof(GotoTop), new PropertyMetadata(ValueBoxes.TrueBox));
+
+        public bool Animated
+        {
+            get => (bool)GetValue(AnimatedProperty);
+            set => SetValue(AnimatedProperty, value);
+        }
+
+        public static readonly DependencyProperty AnimationTimeProperty = DependencyProperty.Register(
+            "AnimationTime", typeof(double), typeof(GotoTop), new PropertyMetadata(ValueBoxes.Double200Box));
+
+        public double AnimationTime
+        {
+            get => (double)GetValue(AnimationTimeProperty);
+            set => SetValue(AnimationTimeProperty, value);
+        }
+
+        public static readonly DependencyProperty HidingHeightProperty = DependencyProperty.Register(
+            "HidingHeight", typeof(double), typeof(GotoTop), new PropertyMetadata(default(double)));
+
+        public double HidingHeight
+        {
+            get => (double)GetValue(HidingHeightProperty);
+            set => SetValue(HidingHeightProperty, value);
+        }
+
+        public static readonly DependencyProperty AutoHidingProperty = DependencyProperty.Register(
+            "AutoHiding", typeof(bool), typeof(GotoTop), new PropertyMetadata(ValueBoxes.TrueBox));
+
+        public bool AutoHiding
+        {
+            get => (bool)GetValue(AutoHidingProperty);
+            set => SetValue(AutoHidingProperty, value);
+        }
+
+        protected override void OnClick()
+        {
+            base.OnClick();
+
+            _gotoTopAction?.Invoke();
+        }
+    }
+}