Question

I have a MVC4 WebAPI controller that returns an IQueryable, and therefore I can use $filter and friends in the URL to manipulate the result from the REST endpoint. Here’s my controller:

public class EnrollmentController : ApiController
{
    [Queryable]
    public IQueryable<tblEnrollment> Get()
    {
        var context = new ProjectEntities();
        context.ContextOptions.LazyLoadingEnabled = false;
        return context.tblEnrollment.AsQueryable();
    }
}

But, like this poster, I’m wanting to make the JSON output format a little different to be friendlier with Ember Data’s expected format. So I’d like to return this instead:

return new { enrollment = context.tblEnrollment.AsQueryable() }; 

However, that breaks OData capability because I’m not returning the IQueryable to the WebAPI layer. So, I’m wondering if there’s a way to do something like this:

return new { enrollment = context.tblEnrollment.AsQueryable().ApplyOData() }; 

Which I’m sure would be way to good to be true…but is there some way to explicitly process the OData parameters against an IQueryable instead of letting the WebAPI layer do it implicitly on the result set returned from a Get method? Or is there another way to accomplish what I want here?

Incidentally, I’m stuck on EF4 for the time being, because I can’t upgrade to VS2012 (and hence to .NET4.5 and hence EF5). I could theoretically upgrade to EF 4.3.1, if it would help.

Answer 1

Instead of marking your action as [Queryable], you can add a parameter of type ODataQueryOptions and apply it manually. Here’s what it might look like:

public class EnrollmentController : ApiController
{
    public object Get(ODataQueryOptions<tblEnrollment> query)
    {
        var context = new ProjectEntities();
        context.ContextOptions.LazyLoadingEnabled = false;
        var queryResults = query.ApplyTo(context.tblEnrollment.AsQueryable());
        return new { enrollment = queryResults };
    }
}