plugin with multi table

I want make a plugin with multi table. When i installed, i code at controller with function get data in a table to show on homepage plugin, but it error at controller.
code controller bellow

[HttpPost]
        public ActionResult GetDuAn(DataSourceRequest command)
        {
            var duAn = _duAnRepository.TableNoTracking.ToList();
            var list = new DataSourceResult
            {
                Data = duAn,
                Total = duAn.Count
            };
            return Json(list);
        }


error when i run this

An exception of type 'System.InvalidOperationException' occurred in EntityFramework.dll but was not handled in user code

Additional information: The entity type DuAnRecord is not part of the model for the current context.


could anyone hepler me? :(((
im a new coder with nop, so i just understand a litter