How to handle UWP KeyDown interaction with Canvas in c#

Question

I've been trying to make this work as part of a game to learn the UWP enviroment when using Canvas. I've read so much on the subject of getting KeyDown to work I'm lost.

Needless to say I hope but none of them seem to work, none cause the event handler to be called.

Any help would be appreciated.

My XAML

    <Grid Background="Black">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="auto" />
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>
        <Canvas Name="paintCanvas" Background="Black" 
                Grid.Column="1" HorizontalAlignment="Stretch" MaxWidth="642" MaxHeight="422"/>
    </Grid>

My simplified code behind:

namespace Game
{
    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();
            paintCanvas.KeyDown += new KeyEventHandler(OnKeyDownHandler);
        }


        private void OnKeyDownHandler(object sender, KeyRoutedEventArgs e)
        {
            switch (e.Key)
            {
                case VirtualKey.Down:
                    // do something
                    break;
                case VirtualKey.Up:
                    // do something
                    break;
                case VirtualKey.Left:
                    // do something
                    break;
                case VirtualKey.Right:
                    // do something
                    break;
            }
        }
    }
}

Not surprisingly, this won't work. A canvas is a Panel, not a Control, so it's not focus-able. The KeyDown event only applies to an Control with input focus. — Jackie
Try declaring a Control(TextBox for instance) inside your canvas, then have it focused. Press the Keyboard to see if the Canvas KeyDown event gets hit. — Jackie
Thanks for the comment. How come the canvas has a KeyDown event then (to name one of many events)?? Does the KeyDown event here fire if it occurs in a child control or should the handler be put in the control's KeyDown event property? — gaw

Jerry Nixon Jerry Nixon · Accepted Answer · 2016-02-03T05:53:56

You can handle this using accelerated keys. You can leverage the KeyHelper in Template 10 if you want some code to steal.

https://github.com/Windows-XAML/Template10/blob/master/Template10%20(Library)/Services/KeyboardService/KeyboardHelper.cs

Then again, you could just use Template 10; in Visual Studio go to Extension Manager and search "Template 10" or add the Template 10 library through Nuget.

Best of luck!

How to handle UWP KeyDown interaction with Canvas in c#

1 Answers