c# - Why my MVC client gets null response from WCF Service? -

i have problem asp.net mvc application. in service folder created wcf service this:

iservice.cs

namespace helloworld {     [servicecontract]     public interface iservice     {         [operationcontract]         list<string> getusers();     } } 

service.svc

<%@ servicehost language="c#" debug="true" service="helloworld.service" codebehind="service.svc.cs" %> 

service.svc.cs

namespace helloworld {     public class service : iservice     {         private applicationdbcontext db = new applicationdbcontext();          public list<string> users = new list<string>();          public list<string> getusers()         {             foreach(var item in db.users.tolist())             {                 users.add(item.username.tostring());             }              return users;         }     } } 

after added service reference mvc client , created following action controller:

// post: simpleclient/create         [httppost]         public actionresult index()         {             userservice.serviceclient objuser = new userservice.serviceclient();              viewbag.users = objuser.getusers().tolist(); // null              return view();         } 

but in index view got null value in viewbag. did make mistake?