Nrthugu

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.

If KeyDown event never fires, chances are that the control handles it internally. MSDN says:

Specific Windows Runtime controls may have class-based handling for the KeyDown input event. If so, the control probably has an override for the method OnKeyDown. Typically these class handlers are intended to process a subset of key presses that enable a keyboard-based user interaction with that control, and often this interaction supports a keyboard accessibility feature. If a key press is handled by class-based handling, then the key press is considered to be already handled, and the KeyDown event is not raised for handling by any user code handlers on that control for that key specifically.

If that's the case you can try overwrite OnKeyDown method to change this behaviour. Unfortunately I can't check now if that's really the problem but maybe this will help you.

Try to use CoreWindow.KeyDown Event instead:

Window.Current.CoreWindow.KeyDown += CoreWindow_KeyDown;

//this.KeyDown += MyDialog_KeyDown;

In addition, if you do not consider the case where the keyboard is not released for a long time, try to use KeyUp event which can be fired normally.

By the way, the Esc key of the keyboard will close the ContentDialog by default, so you need to prevent this feature first in the Closing event.

The compete code:

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;

    }

}

The event you are looking for is PreviewKeyDown event. Keydown event will not get fired if that particular key is handled by system default. PreviewKeyDown fires in all cases.

Note: make sure you set e.handled = false for remaining keys

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;

        }    

    }