private void DeleteWord(object obj)
        {
            WordViewModel word = obj as WordViewModel;

            if (word != null)
            {
                Words.Remove(word);
                App.Database.DeleteWord(word.Id);
            }
            Back();
        }
        private void SaveWord(object obj)
        {
            WordViewModel word = obj as WordViewModel;

            if (Words != null && word.IsValid)
            {
                Words.Add(word);
                App.Database.SaveWord(word.Word);
            }
            Back();
        }