public IActionResult SaveFile(HangHoa model, string FileType, IFormFile fHinh)
        {
            if (ModelState.IsValid)
            {
                //upload file
                var fileName = MyTool.UploadFileToFolder(fHinh, "Data");
                if (fileName == null)
                {
                    fileName = "no_image_available.png";
                }

                model.Hinh = fileName;

                if (FileType == "Save file Text")
                {
                    string[] lines =
                    {
                        model.MaHh.ToString(),    model.TenHh,
                        model.Hinh,               model.DonGia.ToString(),
                        model.GiamGia.ToString(),
                        model.GiaBan.ToString()
                    };

                    System.IO.File.WriteAllLines(textFullPath, lines);
                }
                else if (FileType == "Save file JSON")
                {
                    var json = JsonConvert.SerializeObject(model);
                    System.IO.File.WriteAllText(jsonFullPath, json);
                }
            }

            return(View("Index"));
        }