[Peek]Use space to play/resume video (#29487)

src/modules/peek/Peek.FilePreviewer/FilePreview.xaml

@@ -40,6 +40,9 @@
             Source="{x:Bind VideoPreviewer.Preview, Mode=OneWay}"
             ToolTipService.ToolTip="{x:Bind ImageInfoTooltip, Mode=OneWay}"
             Visibility="{x:Bind IsPreviewVisible(VideoPreviewer, Previewer.State), Mode=OneWay}">
+            <MediaPlayerElement.KeyboardAccelerators>
+                <KeyboardAccelerator Key="Space" Invoked="KeyboardAccelerator_Space_Invoked" />
+            </MediaPlayerElement.KeyboardAccelerators>
             <MediaPlayerElement.TransportControls>
                 <MediaTransportControls
                     x:Name="mediaTransport"

src/modules/peek/Peek.FilePreviewer/FilePreview.xaml.cs

@@ -299,6 +299,28 @@ namespace Peek.FilePreviewer
             }
         }
 
+        private void KeyboardAccelerator_Space_Invoked(KeyboardAccelerator sender, KeyboardAcceleratorInvokedEventArgs args)
+        {
+            var mediaPlayer = VideoPreview.MediaPlayer;
+
+            if (mediaPlayer.Source == null || !mediaPlayer.CanPause)
+            {
+                return;
+            }
+
+            if (mediaPlayer.CurrentState == Windows.Media.Playback.MediaPlayerState.Playing)
+            {
+                mediaPlayer.Pause();
+            }
+            else
+            {
+                mediaPlayer.Play();
+            }
+
+            // Prevent the keyboard accelerator to be called twice
+            args.Handled = true;
+        }
+
         private async Task UpdateImageTooltipAsync(CancellationToken cancellationToken)
         {
             if (Item == null)