I have a domain model that looks like this:
public class Procuct {
string Name {get;set;}
double Price {get;set;}
}
I have a repository that gets some item like so:
public Domain.Product GetProduct(int id) {
// (maps from my ORM model to my domain model)
return ProductMapping.MapProduct(dataService.GetProductEntity(id));
}
I like this because now I have domain models I can work with wherever I need.
In MVC, I want to use this model, with a few extras, so I have a ProductViewModel:
public class ProductViewModel : Domain.Product {
public ViewBase Base {get;set;} // standarized helper stuff in here
}
In my controller, I want to grab a domain object from the repository, and return it as the viewmodel type (where I can then add the Base):
public ActionResult ShowProduct(int productID) {
var model = new ProductViewModel();
model = repository.GetProduct(productID) AS ProductViewModel;
model.Base = new ViewBase() { /* settings here */ };
return View(model);
}
The Smell
This seems like it should work well, but I have a smell about this line that I don't like:
model = repository.GetProduct(productID) AS ProductViewModel;
Apparently downcasting like this tends to be indicative of a less-than-stellar inheritance setup, but I'm not sure how to approach it. Is this generally acceptable if the downcast is to a "light" derived object, or am I doing something particularly wrong here?
What's the correct way to get a domain model into a derived viewmodel?
Further Note
At first I had set up my viewmodel like this:
public class ProductViewModel {
public Domain.Product Product {get;set;}
public ViewBase Base {get; set;}
}
... which actually makes this whole thing very easy because I can just get the domain model and apply it to the property. My issue with this is that I can't it wreaks havoc on the client-side and naming with the UI framework I'm using - far, far easier to have the properties at the "model level" (for lack of better term)
