public async void Undo() { if (undos.Count > 0) { try { var change = await CreateChange("Redo"); redos.Push(change); var undo = undos.Pop(); var block = await Task.Run(() => _itemSerializer.DeserializeContents(undo.Model)); _sheetController.ResetPage(); _sheetController.DeserializePage(block); } catch (Exception ex) { Debug.Print(ex.Message); Debug.Print(ex.StackTrace); } } }