feat: 优化滚动体验. 现在接收消息的时候不会锁定滚动了

Author: SlimeNull

OpenGptChat/Utilities/ScrollViewerUtils.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Controls;
+
+namespace OpenGptChat.Utilities
+{
+    static class ScrollViewerUtils
+    {
+        public static bool IsAtEnd(this ScrollViewer scrollViewer, int threshold = 5)
+        {
+            if (scrollViewer.VerticalOffset == scrollViewer.ScrollableHeight)
+                return true;
+
+            if (scrollViewer.VerticalOffset + threshold >= scrollViewer.ScrollableHeight)
+                return true;
+
+            return false;
+        }
+    }
+}

OpenGptChat/Views/Pages/ChatPage.xaml.cs

@@ -1,10 +1,12 @@
-using System;
+    using System;
 using System.Threading.Tasks;
 using System.Windows;
 using System.Windows.Controls;
+using System.Windows.Input;
 using CommunityToolkit.Mvvm.Input;
 using OpenGptChat.Models;
 using OpenGptChat.Services;
+using OpenGptChat.Utilities;
 using OpenGptChat.ViewModels;
 
 namespace OpenGptChat.Views.Pages
@@ -31,6 +33,8 @@ public ChatPage(
 
             InitializeComponent();
 
+            messageScrollViewer.PreviewMouseWheel += CloseAutoScrollWhileMouseWheel;
+            messageScrollViewer.ScrollChanged += EnableAutoScrollWhileAtEnd;
             smoothScrollingService.Register(messageScrollViewer);
         }
 
@@ -42,6 +46,7 @@ public ChatPage(
 
         public Guid SessionId { get; private set; }
 
+
         public void InitSession(Guid sessionId)
         {
             SessionId = sessionId;
@@ -70,6 +75,10 @@ public async Task SendAsync()
             }
 
 
+            // 发个消息, 将自动滚动打开, 如果已经在底部, 则将自动滚动打开
+            if (messageScrollViewer.IsAtEnd())
+                autoScrollToEnd = true;
+
 
             string input = ViewModel.InputBoxText.Trim();
             ViewModel.InputBoxText = string.Empty;
@@ -117,10 +126,25 @@ public void Copy(string text)
             Clipboard.SetText(text);
         }
 
+
+
+        bool autoScrollToEnd = false;
+
+        private void CloseAutoScrollWhileMouseWheel(object sender, MouseWheelEventArgs e)
+        {
+            autoScrollToEnd = false;
+        }
+
+        private void EnableAutoScrollWhileAtEnd(object sender, ScrollChangedEventArgs e)
+        {
+            if (messageScrollViewer.IsAtEnd())
+                autoScrollToEnd = true;
+        }
+
         [RelayCommand]
         public void ScrollToEndWhileReceiving()
         {
-            if (SendCommand.IsRunning)
+            if (SendCommand.IsRunning && autoScrollToEnd)
                 messageScrollViewer.ScrollToEnd();
         }
     }