WPF 可缩放ScrollView(方式一)

 点击查看方式二

 1     public class ScaleScrollView : ScrollViewer
 2     {
 3         List<object> MouseWheelEvents = new List<object>();
 4         /// <summary>
 5         /// 通过监听此事件对内容进行缩放
 6         /// </summary>
 7         public event MouseWheelEventHandler MouseWheeled
 8         {
 9             add => MouseWheelEvents.Add(value);
10             remove => MouseWheelEvents.Remove(value);
11         }
12 
13         public override void OnApplyTemplate()
14         {
15             base.OnApplyTemplate();
16         }
17 
18         protected override void OnMouseWheel(MouseWheelEventArgs e)
19         {
20             if (e.Handled) { return; }
21 
22             if (ScrollInfo != null)
23             {
24                 //Shift+滚动：上下滚动
25                 //Ctrl+滚动：左右滚动
26                 //滚动：放大缩小
27                 if (Keyboard.IsKeyDown(Key.LeftShift))
28                 {
29                     if (e.Delta > 0)
30                         ScrollInfo.MouseWheelUp();
31                     else
32                         ScrollInfo.MouseWheelDown();
33                 }
34                 else if (Keyboard.IsKeyDown(Key.LeftCtrl))
35                 {
36                     if (e.Delta > 0)
37                         ScrollInfo.LineLeft();
38                     else
39                         ScrollInfo.MouseWheelRight();
40                 }
41                 else
42                 {
43                     foreach (var item in MouseWheelEvents)
44                     {
45                         (item as MouseWheelEventHandler)?.Invoke(this, e);
46                         if (e.Handled) break;
47                     }
48                 }
49             }
50 
51             e.Handled = true;
52         }
53     }

示例：

1 <local:ScaleScrollView HorizontalScrollBarVisibility="Visible" MouseWheeled="ScrollViewer_MouseWheel">
2     <Viewbox Name="viewbox">
3         <Border Width="2000" Height="2000" Background="Orange">
4             <Canvas>
5                 <Rectangle Fill="Red" Width="1000" Height="1000"/>
6             </Canvas>
7         </Border>
8     </Viewbox>
9 </local:ScaleScrollView>
 1         private void ScrollViewer_MouseWheel(object sender, MouseWheelEventArgs e)
 2         {
 3             if (viewbox == null) return;
 4             double w = viewbox.ActualWidth + viewbox.ActualWidth * (e.Delta > 0 ? 1 : -1) / 100;
 5             if (w >= 0)
 6                 viewbox.Width = w;
 7             double h = viewbox.ActualHeight + viewbox.ActualHeight * (e.Delta > 0 ? 1 : -1) / 100;
 8             if (h >= 0)
 9                 viewbox.Height = h;
10         }

配合Slider使用：

<Slider Name="sliderScale" Minimum="1" Value="100" Maximum="1000" SmallChange="1" LargeChange="50" ValueChanged="sliderScale_ValueChanged" Width="100"/>
 1         private void ScrollViewer_MouseWheel(object sender, MouseWheelEventArgs e)
 2         {
 3             sliderScale.Value += e.Delta > 0 ? 1 : -1;
 4         }
 5 
 6         private void sliderScale_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
 7         {
 8             if (viewbox == null) return;
 9             double w = viewbox.ActualWidth + viewbox.ActualWidth * (e.NewValue > e.OldValue ? 1 : -1) / 100;
10             if (w >= 0)
11                 viewbox.Width = w;
12             double h = viewbox.ActualHeight + viewbox.ActualHeight * (e.NewValue > e.OldValue ? 1 : -1) / 100;
13             if (h >= 0)
14                 viewbox.Height = h;
15         }

 

posted @ 2022-03-22 10:04  HotSky  阅读(440)  评论(0)  编辑  收藏  举报