DDWiki/专题/后端/DDD/7、Hi,建造者模式.md

```
    public class ToDoItemBuilder
    {
        private ToDoItem _todo = new ToDoItem();

        public ToDoItemBuilder Id(int id)
        {
            _todo.Id = id;
            return this;
        }

        public ToDoItemBuilder Title(string title)
        {
            _todo.Title = title;
            return this;
        }


        public ToDoItemBuilder Description(string description)
        {
            _todo.Description = description;
            return this;
        }

        public ToDoItemBuilder WithDefaultValues()
        {
            _todo = new ToDoItem { Id = 1, Title = "title", Description = "desc" };
            return this;
        }

        public ToDoItem Build() => _todo;
    }
```



```
    public class ToDoItem : BaseEntity, IAggregateRoot
    {
        public string Title { get; set; } = string.Empty;
        public string Description { get; set; }
        public bool IsDone { get; private set; }

		......
    }
```