DTO objects are used to deserialize data into objects from different sources. Those objects are NOT your Model (POCO) objects. You need to transform those objects into your Model (POCO) objects. The transformation is mostly a copy operation. You can fill those POCO objects directly from the source if its an internal source, but its not adviceable if its an external source. External sources have API's with descriptions of the Schema they use. Its much easier then to load the request data in an DTO and after that transform those in your POCO's. Yes its an extra step, but with a reason. The rule is to load the data from your source in an object. It can be JSON, XML whatever. When loaded then transform that data in what you need in your model. So most of times the DTO is an object image of the external source. Sometimes you even get the Schema's of the source providers then you can deserialize even easier, XML works like that with XSD's.

POCO只是一个不依赖于外部框架的对象。这是显而易见的。

POCO是否有行为无关紧要。

DTO可以是POCO，也可以是域对象(通常行为丰富)。

通常dto更可能依赖于外部框架(例如。属性)用于序列化的目的，因为它们通常在系统的边界处退出。

在典型的Onion风格架构中(通常在广泛的DDD方法中使用)，领域层被放置在中心，因此它的对象在这一点上不应该有该层之外的依赖关系。

DTO的一个主要用例是从web服务返回数据。在这种情况下，POCO和DTO是等价的。POCO中的任何行为在从web服务返回时都将被删除，因此它是否具有行为并不重要。

DTO objects are used to deserialize data into objects from different sources. Those objects are NOT your Model (POCO) objects. You need to transform those objects into your Model (POCO) objects. The transformation is mostly a copy operation. You can fill those POCO objects directly from the source if its an internal source, but its not adviceable if its an external source. External sources have API's with descriptions of the Schema they use. Its much easier then to load the request data in an DTO and after that transform those in your POCO's. Yes its an extra step, but with a reason. The rule is to load the data from your source in an object. It can be JSON, XML whatever. When loaded then transform that data in what you need in your model. So most of times the DTO is an object image of the external source. Sometimes you even get the Schema's of the source providers then you can deserialize even easier, XML works like that with XSD's.

我已经在我的博客文章中阐述了我的立场，所以我在这里发表评论可能是多余的，但那篇文章的最后一段似乎总结了一些事情:

So, in conclusion, learn to love the POCO, and make sure you don’t spread any misinformation about it being the same thing as a DTO. DTOs are simple data containers used for moving data between the layers of an application. POCOs are full fledged business objects with the one requirement that they are Persistence Ignorant (no get or save methods). Lastly, if you haven’t checked out Jimmy Nilsson’s book yet, pick it up from your local university stacks. It has examples in C# and it’s a great read.

顺便说一句，帕特里克，我把POCO当作一篇生活方式的文章来读，我完全同意，这是一篇很棒的文章。这实际上是我推荐的吉米·尼尔森书中的一个章节。我不知道网上也有。他的书确实是我在POCO / DTO / Repository /和其他DDD开发实践方面找到的最好的信息来源。

甚至不要称它们为dto。他们被称为模型....句号。模特从来没有行为。我不知道是谁想出了这个愚蠢的术语DTO，但它一定是一个。net的东西，这是我所能想到的。想想MVC中的视图模型，同样的东西，模型是用来在层与层之间传递状态的服务器端或线上传输，它们都是模型。属性与数据。这些是你传递的模型。模特，模特。就是这样。

我希望DTO这个愚蠢的术语能从我们的词汇表中消失。