private void AddTodoTask(object value)
        {
            TodoTask model = new TodoTask();

            model.Description = value.ToString();
            TodoTaskViewModel viewModel = new TodoTaskViewModel(model);

            TodoTaskItems.Add(viewModel);
        }
        private void LoadTodoTaskFile(object obj)
        {
            TodoTaskItems.Clear();

            System.IO.FileStream   file   = System.IO.File.Open("mytasks.txt", System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.ReadWrite);
            System.IO.StreamReader reader = new System.IO.StreamReader(file);

            while (reader.EndOfStream == false)
            {
                TodoTask todoTask = new TodoTask();
                todoTask.Description = reader.ReadLine();

                TodoTaskItems.Add(new TodoTaskViewModel(todoTask));
            }

            reader.Dispose();
            file.Dispose();
        }