private void LoadThumbnailImage()
{
Debug.Assert(_thumbnail == null);
Debug.Assert(!_isShowingThumbnail);
Debug.Assert(!_isShowingFullSize);
Debug.Assert(!_isLoadingFullSize);
Debug.Assert(!_isLoadingThumbnail);
Debug.Assert(_thumbCancel == null);
Debug.Assert(_fullCancel == null);
_thumbCancel = new CancellationTokenSource();
CancellationToken token = _thumbCancel.Token;
_isLoadingThumbnail = true;
GetURIStream(ThumbnailURI).ContinueWith(task =>
{
if (!token.IsCancellationRequested)
{
Debug.Assert(_thumbCancel.Token == token);
_thumbCancel = null;
_isLoadingThumbnail = false;
}
if (task.IsFaulted || token.IsCancellationRequested)
{
return;
}
UnloadThumbnail();
UnloadFullSize();
_image.SetStreamSource(task.Result, Path.GetExtension(ThumbnailURI.AbsolutePath));
_thumbnail = task.Result;
_isShowingThumbnail = true;
_isShowingFullSize = false;
if (FullSizeURI != null)
{
LoadFullSizeImage();
}
}, TaskContinuationOptions.ExecuteSynchronously);
}