'Generic' ViewModel
Using EF 4, I have several subtypes of a 'Business' entity (customers, suppliers, haulage companies etc). They DO need to be subtypes. I am building a general viewmodel which calls into a service from which a generic repository is accessed.
As I have 4 subtypes, it would be good to have a 'generic' viewmodel used for all of these. Problem is of course is that I have to call a specific type into my generic repository, for example:
BusinessToRetrieve = _repository
.LoadEntity<Customer>(o => o.CustomerID == customerID);
It would be good to be able to call <SomethingElse>
, somethingElse being one or other of the subtypes), otherwise I shall h开发者_如何学Cave to create 4 near identical viemodels, which seems a waste of course! The subtype entity name is available to the viewmodel but I've been unable to figure out how to make the above call convert this into a type. An issue with achieving what I want is that presumably the lambda expression being passed in wouldn't be able to resolve on a 'generic' call ?
It sounds like you need to make yourself familiar with generics. As a start, you'll be able to write code like this:
class ViewModel<T> where T : Business {
public void DoSomething(Func<T, bool> predicate) {
BusinessToRetreive = _repository.LoadEntity<T>(predicate);
}
}
Then you can say:
ViewModel<Customer> c = new ViewModel<Customer>();
c.DoSomething(o => o.CustomerID == customerID);
I'm not sure if this is what you want, but you might be interested in MicroModels
public class EditCustomerModel : MicroModel
{
public EditCustomerModel(Customer customer,
CustomerRepository customerRepository)
{
Property(() => customer.FirstName);
Property(() => customer.LastName).Named("Surname");
Property("FullName", () => string.Format("{0} {1}",
customer.FirstName,
customer.LastName));
Command("Save", () => customerRepository.Save(customer));
}
}
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