Web API 2：OData 4：具有Common Repository的单个控制器在传递给OK方法时不能与IQueryable一起使用

Question

I have tons of entities (created via Database first designer) within my EDMX file. I don't want to create a separate Web Api 2 controller for each entity that I want to expose to my Odata service. That is why my task is to create a SINGLE Web Api 2 OData 4 Controller to return data for any entity that is part of my EntityFramework EDMX file.

I created a GetData(db, "entity name") method to return IQueryable for any entity from the repository dynamically.

My IQueryable< DimUser > Get() method works, but IQueryable Get() (without hard-coded dimUser) does not. The OK method does not do anything and returns me blank result.

I am very frustrated as I don't get any error, and I don't seem to figure out the inner workings of the Ok method.

Question

Is is possible to use IQueryable Get() method instead of IQueryable Get() within my GenericController class?

---

Generic Controller Code

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.ModelBinding;
using System.Web.OData;
using System.Web.OData.Extensions;
using System.Web.OData.Query;
using System.Web.OData.Routing;


using Microsoft.OData.Edm;
using Microsoft.OData.Edm.Library;

using MyDataAccess;
using System.Reflection;

namespace DataService.Controllers
{
    public class GenericController : ODataController
    {
        private Entities db = new MyDataAccess.Entities();

        //HARD-CODING ENTITY NAME RETURNS RESULT, 
        //(but it is not acceptable solution)

        //[EnableQuery(PageSize = 10)]
        //public IQueryable<DimUser> Get()
        //{
        //    return db.DimUsers;
        //}

        //THIS ONE DOES NOT WORK
        [EnableQuery(PageSize = 10)]
        public IQueryable Get()
        {
            var data = GetData(db,"DimUsers");
            return data;
        }

        // Define other methods and classes here
        public IQueryable GetData(MyDataAccess.Entities db, string EntityName)
        {
            foreach (PropertyInfo property in db.GetType().GetProperties())
            {
    var name = property.Name;
    if (name == EntityName)
    {
        var v = property.GetValue(db);
        return (IQueryable)v;
    }
            }
            return null;
        }

    }
}

Register method

public static void Register(HttpConfiguration config)
{
    IList<IODataRoutingConvention> routingConventions = ODataRoutingConventions.CreateDefault();
    routingConventions.Insert(0, new CustomControllerRoutingConvention());
    config.MapODataServiceRoute("EntityDataRoute", "GetEntityData", GenerateEdmModel_Entities(), 
        new DefaultODataPathHandler(), routingConventions);

}

CustomControllerRoutingConvention class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Web;
using System.Web.OData.Routing;
using System.Web.OData.Routing.Conventions;

namespace DataService
{
    public class CustomControllerRoutingConvention : IODataRoutingConvention
    {
        public string SelectAction(ODataPath odataPath, System.Web.Http.Controllers.HttpControllerContext controllerContext, ILookup<string, System.Web.Http.Controllers.HttpActionDescriptor> actionMap)
        {
            return null;
        }

        public string SelectController(ODataPath odataPath, HttpRequestMessage request)
        {
            return "Generic";
        }
    }
}

Answer 1

The solution is to creates an instance of the result with specific result type. see below

   [EnableQuery(PageSize = 10)]
    public IQueryable Get()
    {
        var data = GetData(db,"DimUsers");
        return Okay(data, data.GetType());
    }




    protected IHttpActionResult Okay(object content, Type type)
    {
        var resultType = typeof(OkNegotiatedContentResult<>).MakeGenericType(type);
        return Activator.CreateInstance(resultType, content, this) as IHttpActionResult;
    }