public override void OnActionExecuting(HttpActionContext actionContext)
        {
            // base.OnActionExecuting(actionContext);

            if (!actionContext.ModelState.IsValid)
            {
                var parameter = actionContext.ModelState.Keys.FirstOrDefault().Split('.');

                actionContext.Response = ErrorGenerator.GenerateError(actionContext.Request, parameter.Last(), ErrorCodes.InvalidInputs).Response;
            }
        }