public DataSourceResult GetTks([ModelBinder(typeof(WebApiDataSourceRequestModelBinder))]DataSourceRequest request,
    string client, string matter, string begper, string endper, string History, string Billed, string Unbilled)
 {
    client = client ?? "";
    matter = matter ?? "";
    begper = begper ?? "";
    endper = endper ?? "";
    History = History ?? "";
    Billed = Billed ?? "";
    Unbilled = Unbilled ?? "";
    using (var ctx = new ModelerContext())
    {
       IEnumerable<TkVM> clients = ctx.getTks(client, matter, begper, endper, History, Billed, Unbilled);
       return clients.ToDataSourceResult(request);
    }
 }