Web api different named actions cause Multiple actions error - asp.net-mvc

Question

I have web api 2 controller actions:
[HttpGet]
public Response<IEnumerable<Product>> Get()
{
....(Get all products)
}
[HttpGet]
public Response<Product> Get(int id)
{
....(Get product by id)
}
[HttpGet]
public Response<IEnumerable<Product>> Category(int id)
{
.... (Get products by category)
}
I want to use this controllers with url:
http://localhost/api/product
http://localhost/api/product/1
http://localhost/api/product/category/1
But this url http://localhost/api/product/1 returns error,
Multiple actions were found that match the request
My config settings are like this:
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional }
);
config.Routes.MapHttpRoute(
name: "DefaultApiWithAction",
routeTemplate: "api/{controller}/{action}/{id}",
defaults: new { id = RouteParameter.Optional }
);

Answer 1

You might be better off using attribute routing rather than global routing here. If you remove your global routes and define your routes on a per-action basis you should have no problems. For example, your routes could look like:
[Route("api/product")]
[Route("api/product/{id:int}")]
[Route("api/product/category/{id:int}")]

Answer 2

This is the default controller created when you create a new ASP.NET Web APi within Visual Studio:
[Authorize]
public class ValuesController : ApiController
{
// GET api/values
public IEnumerable<string> Get()
{
return new string[] { "value1", "value2" };
}
// GET api/values/5
public string Get(int id)
{
return "value";
}
// POST api/values
public void Post([FromBody]string value)
{
}
// PUT api/values/5
public void Put(int id, [FromBody]string value)
{
}
// DELETE api/values/5
public void Delete(int id)
{
}
}
And the WebApi config:
public static class WebApiConfig
{
public static void Register(HttpConfiguration config)
{
// Web API configuration and services
// Configure Web API to use only bearer token authentication.
config.SuppressDefaultHostAuthentication();
config.Filters.Add(new HostAuthenticationFilter(OAuthDefaults.AuthenticationType));
// Web API routes
config.MapHttpAttributeRoutes();
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional }
);
}
}

Answer 3

Your two Get methods match the same route. I would delete the first Get method and change your second Get method to use an optional id parameter like so:
[HttpGet]
public Response<IEnumerable<Product>> Get(int? id)
{
// Get all products if id is null, else get product by id and return as a list with one element
}
This way, Get will match routes for both "product" and "product/1".