Automatically expand related entity with OData Controller

Question

Hello,

 

I'm writing an API to allow a supplier to connect to us. They've specified how they want it.

 

For one part they want a GET action for Items. An Item has a colletion o f prices in it.

 Normally I woul use $expand in de the OData URL, but that is not allowed.

 

Soo, is it possible to add tehe xpand in code in tehe controller?

 

I've tried, but cant'get it to work.

Here is my code so far:

 

 public class Items 
    {     [Key]
          public Guid Id { get; set; }  
          public string ItemCode { get; set; }
          public decimal SalesPriceExcl { get; set; } 
          public decimal SalesPriceIncl { get; set; }
          public virtual ICollection<ItemPrice> SalesPrices { get; set; } 
          public Items() 
          {
             SalesPrices = new HashSet<App4Sales_ItemPrice>();     
          }
 }

 public class ItemPrice
 {
    [Key, Column(Order = 0), ForeignKey("Items")]
    public Guid Id { get; set; }
    public virtual Items Items { get; set; } 
    [Key, Column(Order=1)]
    public Guid PriceList { get; set; } 
    public decimal PriceExcl { get; set; }
    public decimal PriceIncl { get; set; }
    public decimal VatPercentage { get; set; }  
}

And the controller:
  // GET: odata/Items 
  //[Queryable]
  public IQueryable<Items> GetItems(ODataQueryOptions opts)
 {         
   SelectExpandQueryOption expandOpts = new SelectExpandQueryOption(null, "SalesPrices", opts.Context);         
   Request.SetSelectExpandClause(expandOpts.SelectExpandClause);
    return expandOpts.ApplyTo(db.Items.AsQueryable(), new ODataQuerySettings()) as IQueryable<Items>;      
 }

This results in the following error:
Unable to cast object of type  
'System.Data.Entity.Infrastructure.DbQuery1[System.Web.Http.OData.Query.Expressions.SelectExpandBinder+SelectAllAndExpand1[.Models.Items]]'  to type '.Models.Items'.

Anyone ideas how to pass this?

 

Jeroen