SHIFT + 滚动以在 ScrollViewer UWP 中水平滚动

Question

我想启用在滚动时按住键盘上的 SHIFT 以水平滚动 ScrollViewer。

我从here that the PointerWheelChanged event is the one I am looking for. Handling that, however, doesn't work because the ScrollViewer handles it internally, so my handler is never called. To get around that, I used the AddHandler method, as described in the "Routed Events Overview"文章中学到了。

这有效...但在 ScrollViewer 运行其内部代码后似乎是运行我的代码。结果是 ScrollViewer 内容垂直平移，然后水平平移。它们似乎按此顺序发生，设置 e.Handled = true 不会阻止它。

有没有办法 "intercept" 滚动，这样我就可以用我自己的逻辑来处理它，从而允许 ScrollViewer 在按下 SHIFT 时水平平移？我最近问了一个类似的问题（涉及拦截控件的输入，以便我可以用自己的逻辑处理它），答案涉及处理不同的事件，该事件发生在控制之前运行自己的逻辑。我没有看到类似的 "pre stuff happening" 指针滚动事件。

我的代码如下。请注意 ScrollViewer 可以水平和垂直滚动，也可以缩放：

<!-- Contained in Grid in a UserControl, if that's relevant -->
<ScrollViewer Name="MyCanvasScrollViewer"
              VerticalScrollBarVisibility="Auto"
              HorizontalScrollBarVisibility="Auto"
              ZoomMode="Enabled"
              ZoomSnapPointsType="Optional"
              PointerWheelChanged="MyCanvasScrollViewer_PointerWheelChanged">
    <!-- Content to pan -->
</ScrollViewer>

代码隐藏：

// Constructor for the user contol.
public MyControl()
{
    // Add the scroll wheel event handler and force it to run.
    this.MyCanvasScrollViewer.AddHandler(ScrollViewer.PointerWheelChangedEvent, new PointerEventHandler(this.MyCanvasScrollViewer_PointerWheelChanged), true);

    // Other un-related stuff omitted here...
}

// Event handler for the Pointer Wheel Changed event.
private void MyCanvasScrollViewer_PointerWheelChanged(object sender, PointerRoutedEventArgs e)
{
    // If SHIFT is pressed...
    var keyState = CoreWindow.GetForCurrentThread().GetKeyState(VirtualKey.Shift);
    if ((keyState & CoreVirtualKeyStates.Down) == CoreVirtualKeyStates.Down)
    {
        // Get the amount to scroll.
        PointerPoint pointer = e.GetCurrentPoint(this.WallCanvasScrollViewer);
        double scrollWheelDelta = pointer.Properties.MouseWheelDelta;

        // Change the view in the scroll viewer.
        this.MyCanvasScrollViewer.ChangeView(scrollWheelDelta, null, null, true);

        // Mark event as handled.
        e.Handled = true;
    }
}

Answer 1

您可以简单地在 shift keydown 中禁用 VerticalScrollMode 并在 keyup 中启用它。不需要 pointerwheelchanged 本身。它工作得很好。

Xaml

<ScrollViewer ZoomMode="Enabled" x:Name="MyScrollViewer"  HorizontalScrollMode="Enabled" HorizontalScrollBarVisibility="Visible" >
   <Image Height="600" Width="500" Source="/Assets/1.jpg"></Image>
</ScrollViewer>

//C#代码

public sealed partial class MainPage : Page
{
    public MainPage()
    {
        this.InitializeComponent();
        CoreWindow.GetForCurrentThread().KeyDown += MainPage_KeyDown;
        CoreWindow.GetForCurrentThread().KeyUp += MainPage_KeyUp; ;
    }

    private void MainPage_KeyUp(CoreWindow sender, KeyEventArgs args)
    {
        if (args.VirtualKey == VirtualKey.Shift)
        {                
            MyScrollViewer.IsScrollInertiaEnabled = true;
            MyScrollViewer.VerticalScrollMode = ScrollMode.Enabled;
        }
    }

    private void MainPage_KeyDown(CoreWindow sender, KeyEventArgs args)
    {
        if (args.VirtualKey == VirtualKey.Shift)
        {
            MyScrollViewer.IsScrollInertiaEnabled = false;
            MyScrollViewer.VerticalScrollMode = ScrollMode.Disabled;
        }
    }

}

SHIFT + 滚动以在 ScrollViewer UWP 中水平滚动

SHIFT + Scroll to Scroll Horizontally in ScrollViewer UWP

c#

xaml

event-handling

scrollviewer

uwp