Passing querystring parameters without using OData conventions?

Question

Is there a way to pass querystring parameters to an ASP.NET MVC4 Web Api controller without using the OData conventions outlined here?

http://www.asp.net/web-api/overview/web-api-routing-and-actions/paging-and-querying

I have some repository methods built using Dapper that don't support IQueryable and want to be able to manually paginate them without using the OData conventions, but whenever I try doing it the traditional ASP.NET way I get "route not found" errors.

For instance, here's a route:

context.Routes.MapHttpRoute(
           name: "APIv1_api_pagination",
           routeTemplate: "api/v1/{controller}/{id}",
           defaults: new { area = AreaName, controller = "category", offset = 0, count = 100});

And here's the signature to match

public class CategoryController : ApiController
{
    // GET /api/<controller>
    public HttpResponseMessage Get(int id, int offset = 0, int count = 0)

And whenever I pass the following query:

http://localhost/api/v1/category/1?offset=10

I get the following error:

No action was found on the controller 'Category' that matches the request.

Any suggestions on how to work with querystrings sanely in ASP.NET MVC4 Web Api?

Answer 1

When you start to use querystring you actually call exact method of controller with its parameters. What I prefer you to change your router like :

context.Routes.MapHttpRoute(
       name: "APIv1_api_pagination",
       routeTemplate: "api/v1/{controller}/{action}/{id}",
       defaults: new { area = AreaName, controller = "category", offset = 0, count = 100});

and then change your method into

public HttpResponseMessage Items(int id, int offset = 0, int count = 0);

From now on whenever you query like

http://localhost/api/v1/category/Items?id=1&offset=10&count=0

it will run.

Another method came to my mind while writing this. I don't know if it works but try to change your router like

context.Routes.MapHttpRoute(
       name: "APIv1_api_pagination",
       routeTemplate: "api/v1/{controller}/{id}/{offset}/{count}",
       defaults: new { area = AreaName, controller = "category", offset = RouteParameter.Optional, count = RouteParameter.Optional});

Answer 2

In this instance, the issue I was running into was the fact that I had multiple overloads for GET on my WebApi controller instance. When I removed those (and condensed everything down to one Get method with more optional parameters and control-flow inside the method itself) everything worked as expected.