Why can't these generic type parameters be inferred?
- by Jon M
Given the following interfaces/classes:
public interface IRequest<TResponse> { }
public interface IHandler<TRequest, TResponse>
where TRequest : IRequest<TResponse>
{
TResponse Handle(TRequest request);
}
public class HandlingService
{
public TResponse Handle<TRequest, TResponse>(TRequest request)
where TRequest : IRequest<TResponse>
{
var handler = container.GetInstance<IHandler<TRequest, TResponse>>();
return handler.Handle(request);
}
}
public class CustomerResponse
{
public Customer Customer { get; set; }
}
public class GetCustomerByIdRequest : IRequest<CustomerResponse>
{
public int CustomerId { get; set; }
}
Why can't the compiler infer the correct types, if I try and write something like the following:
var service = new HandlingService();
var request = new GetCustomerByIdRequest { CustomerId = 1234 };
var response = service.Handle(request); // Shouldn't this know that response is going to be CustomerResponse?
I just get the 'type arguments cannot be inferred' message. Is this a limitation with generic type inference in general, or is there a way to make this work?
