Inherited Web API API Controller

Question

I have a couple of classes

Square : Rectangle : Shape (abstract)

and I have a Base Controller inheriting from ApiController that I'd like to use.

public abstract class BaseController<T> : ApiController where T : class
{
    public abstract IEnumerable<T> Get()
    ...
}

and

public class DerivedController : BaseController<Rectangle>
{
    public override IEnumerable<Rectangle> Get()
    ...
}

public class AnotherDerivedController : BaseController<Square>
{
    public new IEnumerable<Square> Get()
    ...
}

/api/rectangle will properly call IEnumerable<Rectangle> Get()

/api/square will give me an error:

Multiple actions were found that match the request: 
System.Linq.IEnumerable`1[Square] Get() on type Web.Api.Controllers.AnotherDerivedController 
System.Linq.IEnumerable`1[Rectangle] Get() on type Web.Api.Controllers.DerivedController

If I change public new IEnumerable<Square> Get() to public override IEnumerable<Square> Get(), I get a compile time error since the return signatures are different

How do I get my code to call the proper method? Is it necessary to explicitly register each class's methods in RegisterRoutes?

Aliostad · Accepted Answer · 2012-04-18 22:49:55Z

1

You need to override the Get, you are basically using it with new. This is not gonna work since the class will have two Get methods and Web API will be confused to pick which one.

You may define the BaseController as abstract and Get as virtual or abstract and then implement in your DerivedController.

answered Apr 18, 2012 at 22:49

Aliostad

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khaihon Over a year ago

Hi Aliostad, I updated my question to reflect your changes. I'm still getting some problems here, but your suggestions were helpful to me. Thanks.

Aaron Fischer · Accepted Answer · 2012-04-19 14:21:05Z

0

You currently have two controllers that can take your square class. How are you registering your routes? If you rename the controlers to rectangleController and SquareController you will probably be fine.

answered Apr 19, 2012 at 14:21

Aaron Fischer

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khaihon Over a year ago

Right now, I just have the default route

routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional });

In my actual code, I do have (RectangleController) and (SquareController)... but it is still not routing correctly, giving me the same error message.

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