public ViewModeViewModel(string viewMode)
 {
     _viewMode     = viewMode;
     _viewModeIcon = new Lazy <ImageSource>(
         () =>
     {
         try
         {
             Stream imgStream = Application.GetResourceStream(
                 new Uri(String.Format(iconPathMask, ViewMode.ToLower()))).Stream;
             BitmapDecoder decoder = IconBitmapDecoder.Create(imgStream, BitmapCreateOptions.None, BitmapCacheOption.None);
             return(decoder.Frames[0]);
         }
         catch (Exception ex)
         {
             throw ex;
         }
     });
 }