public static async Task UpdateThumbImageSourceAsync(this SeekBar seekBar, ISlider slider, IImageSourceServiceProvider provider, Drawable?defaultThumb) { var context = seekBar.Context; if (context == null) { return; } var thumbImageSource = slider.ThumbImageSource; if (thumbImageSource != null) { var service = provider.GetRequiredImageSourceService(thumbImageSource); var result = await service.GetDrawableAsync(thumbImageSource, context); Drawable?thumbDrawable = result?.Value; if (seekBar.IsAlive()) { seekBar.SetThumb(thumbDrawable ?? defaultThumb); } } }