Question

So I have a Button in Xaml:

    <Button x:Name="btnCancel"
            Click="btnCancel_Click"
            Content="Cancel"></Button>

and in a ContentDialog I want to press a Key to trigger that button. My Problem is that no key presses are recognized and I don´t understand why.

.cs:

public sealed partial class MyDialog : ContentDialog
{
    public MyDialog()
    {
        this.InitializeComponent();
        this.Loaded += MyDialog_Loaded;

        this.Closing += ContentDialog_Closing;
        this.KeyDown += onE_KeyDown;   
    }

//...

    private void onE_KeyDown(object sender, KeyRoutedEventArgs e)
    {
        if (e.Key == Windows.System.VirtualKey.Escape)
        {
            //btnCancel_Click(sender, e); 
            btnCancel_Click(this, new RoutedEventArgs());
        }
    }

    void ContentDialog_Closing(ContentDialog sender, ContentDialogClosingEventArgs args)
    {
        args.Cancel = syncInProcess;
       // btnCancel_Click(this, new RoutedEventArgs());
    }
}

I put a breakpoint at the onE_KeyDown method but it never gets there.

Answer 1

如果KeyDown事件从不触发，则该控件很可能在内部对其进行处理。 MSDN说：

特定的Windows运行时控件可能对KeyDown输入事件具有基于类的处理。如果是这样，则控件可能会覆盖方法OnKeyDown。通常，这些类处理程序旨在处理按键的子集，以使基于键盘的用户与该控件进行交互，并且这种交互通常支持键盘可访问性功能。如果某个按键是通过基于类的处理来处理的，则认为该按键已被处理，并且该控件上的任何用户代码处理程序都不会引发KeyDown事件来专门处理该按键。

在这种情况下，您可以尝试覆盖OnKeyDown method来更改此行为。不幸的是，我现在无法检查这是否真的是问题所在，但这也许会对您有所帮助。

Answer 2

尝试改用CoreWindow.KeyDown Event：

Window.Current.CoreWindow.KeyDown += CoreWindow_KeyDown;
//this.KeyDown += MyDialog_KeyDown;

此外，如果您不考虑长时间不释放键盘的情况，请尝试使用可以正常触发的 KeyUp事件 。< / p>

顺便说一句，默认情况下，键盘的Esc键将关闭ContentDialog ，因此您需要在Closing事件中首先阻止此功能。

比赛代码：

public MyDialog()
{
    this.InitializeComponent();
    this.Loaded += MyDialog_Loaded;

    this.Closing += ContentDialog_Closing;
    //this.KeyDown += onE_KeyDown;
    this.KeyUp += MyDialog_KeyUp;
}

private void MyDialog_KeyUp(object sender, KeyRoutedEventArgs e)
{
    if (e.Key == Windows.System.VirtualKey.Escape)
    {
        //btnCancel_Click(sender, e); 
        btnCancel_Click(this, new RoutedEventArgs());
    }
}

void ContentDialog_Closing(ContentDialog sender, ContentDialogClosingEventArgs args)
{
    //args.Cancel = syncInProcess;
    // btnCancel_Click(this, new RoutedEventArgs());
    if (args.Result == ContentDialogResult.None)
    {
        args.Cancel = true;
    }
}

Answer 3

您要查找的事件是 PreviewKeyDown 事件。如果系统默认处理该特定键，则不会触发Keydown事件。在所有情况下都会触发PreviewKeyDown。

注意：请确保您为其余键设置e.handled = false

https://docs.microsoft.com/en-us/uwp/api/windows.ui.xaml.uielement.previewkeydown

 <ContentDialog
    x:Class="App1.NewContentDialog"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:App1"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Title="TITLE"
    PreviewKeyDown="ContentDialog_PreviewKeyDown"
    PrimaryButtonText="Button1"
    SecondaryButtonText="Button2"
    PrimaryButtonClick="ContentDialog_PrimaryButtonClick"
    SecondaryButtonClick="ContentDialog_SecondaryButtonClick">

    <Grid>
    </Grid>
</ContentDialog>


private void ContentDialog_PreviewKeyDown(object sender, KeyRoutedEventArgs e)
    {
        if (e.Key == Windows.System.VirtualKey.Escape)
        {
            btnCancel_Click(this, new RoutedEventArgs());
        }
        else
        {
            e.Handled = false;
        }    
    }

Pressing a key in ContentDialog

3 个答案: