I am considering to use DTOs instead of passing around my domain objects. I have read several posts here as well as elsewhere, and i understand there are several approaches to getting this done.
If i only have about 10 domain classes in all, and considering that i want to use DTOs rather than domain objects for consumption in my Views (WPF front ends), what is the recommended approach. I think using tools like automapper etc maybe an overkill for my situation. So i am thinking of writing my custom mapper class that will have methods for converting a domain type to a DTO type.
What is the best way to do this, are there any sample to get me started to do this?
Second question: When writing those methods that will create DTOs, how do i deal with setting up all the data, especially when the domain type has references to other domain objects? Do i write equivalent properties in the DTO for mapping to those refernece types in the domain class? Please ask if i have not put my second question in proper words. But i think you understand what i am trying to ask.
Thrid question: When writing DTOs, should i write multiple DTOs, each containing partial data for a given domain model, so that each of it can be used to cater to a specific View's requirement, or should the DTO have all the data that are there in the corresponding model class.
Answer
I've been reading a few posts here regarding DTO's and it seems to me that a lot of people equate them to what I would consider a ViewModel. A DTO is just that, Data Transfer Object - it's what gets passed down the wire. So I've got a website and services, only the services will have access to real domain/entity objects, and return DTO's. These may map 1:1, but consider that the DTO's may be populated from another service call, a database query, reading a config - whatever.
After that, the website then can take those DTO and either add them to a ViewModel, or convert into one. That ViewModel may contain many different types of DTO's. A simple example would be a task manager - the ViewModel contains both the task object you are editing, as well as a group of Dto.User objects that the task can be assigned to.
Keep in mind that the services returning DTO's maybe used by both a website, and maybe a tablet or phone application. These applications would have different views to take advantage of their displays and so the ViewModels would differ, but the DTO's would remain the same.
At any rate, I love these types of discussions, so anyone please let me know what you think.
Matt