Odata action returning collection of the same entity set

Question

I'm trying to get my Odata enpoint to have an action that returns the same DataType as the controller it's on.

I tried the following in my WebApiConfig:

var entity = builder.EntitySet<Entity>("entities");
             builder.Entity<Entity>().Action("UnassignedMarkets").ReturnsCollection<Entity>();

I'm getting the following error

An exception of type 'System.InvalidOperationException' occurred in System.Web.Http.OData.dll but was not handled in user code Additional information: The EDM type 'MyProj.DataAccess.Views.Entity' is already declared as an entity type. Use the method 'ReturnsCollectionFromEntitySet' if the return type is an entity collection.

So I change my code to the following and it compiles

var entity = builder.EntitySet<Entity>("entities");
             builder.Entity<Entity>().Action("UnassignedMarkets").ReturnsCollectionFromEntitySet<Entity>("entities");

I browse to the action using fiddler

http://localhost:777/odata/entities/UnassignedMarkets

which returns:

{ "message": "The OData path is invalid.", "exceptionMessage": "Invalid action detected. 'UnassignedMarkets' is not an action that can bind to 'Collection([MyProj.DataAccess.Dtos.Views.Entity Nullable=False])'.", "exceptionType": "Microsoft.Data.OData.ODataException", "stackTrace": " at System.Web.Http.OData.Routing.DefaultODataPathHandler.ParseAtEntityCollection(IEdmModel model, ODataPathSegment previous, IEdmType previousEdmType, String segment)\r\n at System.Web.Http.OData.Routing.DefaultODataPathHandler.ParseAtCollection(IEdmModel model, ODataPathSegment previous, IEdmType previousEdmType, String segment)\r\n at System.Web.Http.OData.Routing.DefaultODataPathHandler.ParseNextSegment(IEdmModel model, ODataPathSegment previous, IEdmType previousEdmType, String segment)\r\n at System.Web.Http.OData.Routing.DefaultODataPathHandler.Parse(IEdmModel model, String odataPath)\r\n at System.Web.Http.OData.Routing.ODataPathRouteConstraint.Match(HttpRequestMessage request, IHttpRoute route, String parameterName, IDictionary`2 values, HttpRouteDirection routeDirection)" }

public class EntitiesController : ODataController
{
     private readonly Storage _storage;

     public EntitiesController(Storage storage)
     {
            _storage = storage;
     }

     [Queryable]
     public IQueryable<Entity> Get()
     {
        return _storage.Entities;
     }


     [HttpPost]
     public IQueryable<Entity> UnassignedMarkets(ODataQueryOptions<Entity> queryOptions)
     {
         return buildEntities();
     }
}

Feng Zhao Feng Zhao · Accepted Answer · 2014-07-27T07:00:06

According to your request:

http://localhost:777/odata/entities/UnassignedMarkets

the action "UnassignedMarkets" is bound to collection of entity.

So you can try the code below to build your model:

var entity = builder.EntitySet<Entity>("entities");
builder.Entity<Entity>().Collection.Action("UnassignedMarkets").ReturnsCollectionFromEntitySet<Entity>("entities");

Odata action returning collection of the same entity set

1 Answers