How to convert json items to collection of objects in MVC?

public Collection<ItemName> ItemNames { get; set; }
<pre lang="xml">public ActionResult GetItemList(int RRGroupID, int InstitutionID)
       {

         var item = ReportEngineHelper.GetReportingEngine(Session).Generate&lt;ItemListQuery&gt;(new Filter()
           {
               Item=new ItemaRR()
               {
                   RRGroupID = RRGroupID,
                   InstitutionID = InstitutionID,
               }
           }).ToQueryModel&lt;ItemName&gt;();

           return Json(item, JsonRequestBehavior.AllowGet);
       }</pre>