public TodoItemsListVm(ITodoItemsService todoItemsService)
{
this.todoItemsService = todoItemsService;
// Firstly get all items, and after that watch to changes.
todoItemsService.GetAll()
.Select(items => items.Select(todoItem => new TodoItemVm(todoItem)))
.Do(items => TodoItems.AddRange(items))
.SelectMany(_ => todoItemsService.TodoItemAdded)
.Subscribe(todoItem => TodoItems.Add(new TodoItemVm(todoItem)));
this.WhenAnyValue(x => x.SelectedTodoItem)
.Where(todoItem => todoItem != null)
.Select(todoItem => todoItem.Model)
.SelectMany(todoItem => todoItemsService.SetCurrentTodoItem(todoItem))
.Subscribe();
}