2025-07-15 19:13

2026-03-03 00:00:56 +08:00 · 2025-07-15 19:14:03 +08:00
parent ebc05c28b9
commit ca823a9294
3 changed files with 125 additions and 48 deletions
--- a/VisionFrame/Extensions/ScrollViewerExtensions.cs
+++ b/VisionFrame/Extensions/ScrollViewerExtensions.cs
@@ -0,0 +1,68 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows;
+using System.Windows.Controls;
+
+namespace VisionFrame.Extensions
+{
+    public class ScrollViewerExtensions
+    {
+        public static readonly DependencyProperty AlwaysScrollToEndProperty = DependencyProperty.RegisterAttached("AlwaysScrollToEnd", typeof(bool), typeof(ScrollViewerExtensions), new PropertyMetadata(false, AlwaysScrollToEndChanged));
+        private static bool _autoScroll;
+
+
+        private static void AlwaysScrollToEndChanged(object sender, DependencyPropertyChangedEventArgs e)
+        {
+            ScrollViewer scroll = sender as ScrollViewer;
+            if (scroll != null)
+            {
+                bool alwaysScrollToEnd = (e.NewValue != null) && (bool)e.NewValue;
+                if (alwaysScrollToEnd)
+                {
+                    scroll.ScrollToEnd();
+                    scroll.ScrollChanged += ScrollChanged;
+                    // scroll.SizeChanged += Scroll_SizeChanged;
+                }
+                else { scroll.ScrollChanged -= ScrollChanged; /*scroll.ScrollChanged -= ScrollChanged; */}
+            }
+            else { throw new InvalidOperationException("The attached AlwaysScrollToEnd property can only be applied to ScrollViewer instances."); }
+        }
+
+
+        //private static void Scroll_SizeChanged(object sender, SizeChangedEventArgs e)
+        //{
+        //    ScrollViewer scroll = sender as ScrollViewer;
+        //    if (scroll == null) { throw new InvalidOperationException("The attached AlwaysScrollToEnd property can only be applied to ScrollViewer instances."); }
+        //    double d = scroll.ActualHeight + scroll.ViewportHeight + scroll.ExtentHeight;
+        //    scroll.ScrollToVerticalOffset(d);
+        //}
+
+
+        public static bool GetAlwaysScrollToEnd(ScrollViewer scroll)
+        {
+            if (scroll == null) { throw new ArgumentNullException("scroll"); }
+            return (bool)scroll.GetValue(AlwaysScrollToEndProperty);
+        }
+
+
+        public static void SetAlwaysScrollToEnd(ScrollViewer scroll, bool alwaysScrollToEnd)
+        {
+            if (scroll == null) { throw new ArgumentNullException("scroll"); }
+            scroll.SetValue(AlwaysScrollToEndProperty, alwaysScrollToEnd);
+        }
+
+
+        private static void ScrollChanged(object sender, ScrollChangedEventArgs e)
+        {
+            ScrollViewer scroll = sender as ScrollViewer;
+            if (scroll == null) { throw new InvalidOperationException("The attached AlwaysScrollToEnd property can only be applied to ScrollViewer instances."); }
+
+
+            if (e.ExtentHeightChange == 0) { _autoScroll = scroll.VerticalOffset == scroll.ScrollableHeight; }
+            if (_autoScroll && e.ExtentHeightChange != 0) { scroll.ScrollToVerticalOffset(scroll.ExtentHeight); }
+        }
+    }
+}