Question

我在Window.Current.CoreWindow上使用KeyDown和KeyUp处理程序来捕获UWP的VNC应用程序中的击键。这有一个例外：alt（VirtualKey.Menu/LeftMenu/RightMenu）永远不会发送到我的应用程序。此外，alt +字母也不会发送给处理程序。

我认为这是因为某些加速器处理程序在到达CoreWindow之前正在吃这些事件。有没有办法解决这个问题？

Answer 1

尝试使用Dispatcher.AcceleratorKeyActivated，它会处理Alt键。

此外，似乎CoreWindow存在问题。有关MSDN

的更多详情

Answer 2

下面是我如何在Xamarin Forms中解决此问题的示例。

// A model to store the values of the key event.
public class KeyEventArgs : EventArgs
{
    public bool IsAltKeyPressed { get; set; }

    public string Key { get; set; }
}

// UWP Custom render
public class MyPageViewRenderer : PageRenderer
{
    /// <summary>
    /// Monitor windows core ui keypress when MyPageView is showing
    /// </summary>
    public MyPageViewRenderer() : base()
    {
        // When ExplorePage appears then attach to the ui core keydown event
        Loaded += (object sender, RoutedEventArgs e) =>
        {
            CoreWindow.GetForCurrentThread().Dispatcher.AcceleratorKeyActivated += Dispatcher_AcceleratorKeyActivated;
        };

        // When ExplorePage disappears then detach from the ui core keydown event
        Unloaded += (object sender, RoutedEventArgs e) =>
        {
            CoreWindow.GetForCurrentThread().Dispatcher.AcceleratorKeyActivated -= Dispatcher_AcceleratorKeyActivated;
        };
    }

    private void Dispatcher_AcceleratorKeyActivated(CoreDispatcher sender, AcceleratorKeyEventArgs args)
    {
        if ((args.EventType == CoreAcceleratorKeyEventType.KeyDown || args.EventType == CoreAcceleratorKeyEventType.SystemKeyDown)
            && !args.KeyStatus.WasKeyDown)
        {
            bool isAltKeyPressed = args.KeyStatus.IsMenuKeyDown;
            (Element as MyPageView).MyPageView_KeyPressed(Element, new KeyEventArgs { IsAltKeyPressed = isAltKeyPressed, Key = args.VirtualKey.ToString() });
        }
    }
}

[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class MyPageView : ContentPage
{
    public MyPageView()
    {
        InitializeComponent();

        this.Focus();
    }

    public void MyPageView_KeyPressed(object sender, KeyEventArgs e)
    {

        (this.BindingContext as MyPageViewModel).CommandOnKeyPress?.Execute(e);
        
    }
}

处理UWP应用程序

2 个答案: