public IActionResult listbyid([FromQuery(Name = "id")] int id)
 {
     if (id > 0)
     {
         return(StatusCode(StatusCodes.Status200OK, Json(pr.listbyid(id))));
     }
     else
     {
         return(StatusCode(StatusCodes.Status406NotAcceptable,
                           Json(new error {
             request = 1, response = "No se encontro el producto"
         })));
     }
 }