public async void Loaded()
 {
     foreach (var knownFolder in ShellKnownFolders.EnumerateKnownFolders())
     {
         this.KnownFolders.Add(await ShellKnownFolderViewModel.CreateAsync(knownFolder));
     }
 }
        public static Task <ShellKnownFolderViewModel> CreateAsync(ShellKnownFolder shellKnownFolder)
        {
            return(Task.Run(() =>
            {
                var result = new ShellKnownFolderViewModel(shellKnownFolder);
                result.Thumbnail.Value = new ShellImageSource(shellKnownFolder.GetThumbnail(ThumbnailMode.ListView));

                return result;
            }));
        }