C#

<mmppf:MediaPlayer x:Name="YoutubePlayer" Visibility="Visible" IsFullScreenVisible="True"
IsFullScreenChanged="YoutubePlayer_IsFullScreenChanged"
Stretch="UniformToFill" MediaQuality="HighDefinition"
IsResolutionIndicatorVisible="True" IsSignalStrengthVisible="False" IsAudioSelectionVisible="True" IsPlayPauseVisible="True"
IsSkipAheadVisible="True" IsSkipBackVisible="True"
MediaOpened="YoutubePlayer_MediaOpened"
MediaEnded="YoutubePlayer_MediaEnded"
MediaQualityChanged="YoutubePlayer_MediaQualityChanged" ></mmppf:MediaPlayer>

private async void YoutubePlayer_IsFullScreenChanged(object sender, RoutedPropertyChangedEventArgs<bool> e)
    {
        try
        {

        }
        catch(Exception ex)
        {
            var dialog = new MessageDialog(ex.Message);
            dialog.ShowAsync();
        }

    }