ASP.NET MVC Excel ile ürün ekleme hatası

public ActionResult ProducAdd()
        {
            return View();
        }

        [HttpPost]
        public JsonResult UploadExcel(Products p, HttpPostedFileBase FileUpload)
        {
           
            List<string> data = new List<string>();
            if (FileUpload != null)
            {
                // tdata.ExecuteCommand("truncate table OtherCompanyAssets");
                if (FileUpload.ContentType == "application/vnd.ms-excel" || FileUpload.ContentType == "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
                {
                    string filename = FileUpload.FileName;
                    string targetpath = Server.MapPath("~/Content/");
                    FileUpload.SaveAs(targetpath + filename);
                    string pathToExcelFile = targetpath + filename;
                    var connectionString = "";
                    if (filename.EndsWith(".xls"))
                    {
                        connectionString = string.Format("Provider=Microsoft.ACE.OLEDB.12.0; data source={0}; Extended Properties=Excel 12.0;", pathToExcelFile);
                    }
                    else if (filename.EndsWith(".xlsx"))
                    {
                        connectionString = string.Format("Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties=\"Excel 12.0 Xml;HDR=YES;IMEX=1\";", pathToExcelFile);
                    }

                    var adapter = new OleDbDataAdapter("SELECT * FROM [Sheet1$]", connectionString);
                    var ds = new DataSet();
                    adapter.Fill(ds, "ExcelTable");
                    DataTable dtable = ds.Tables["ExcelTable"];
                    string sheetName = "Sheet1";
                    var excelFile = new ExcelQueryFactory(pathToExcelFile);
                    var artistAlbums = from a in excelFile.Worksheet<Products>(sheetName) select a;
                    foreach (var a in artistAlbums)
                    {
                        try
                        {
                            if (a.Number != "" && a.Name != "")
                            {
                                Products pr = new Products();
                                pr.Number = a.Number;
                                pr.Name = a.Name;
                                pr.Model = a.Model;
                                pr.Price = a.Price;
                                pr.Stock = a.Stock;
                                pr.AddedDate = DateTime.Now;
                                pr.ModifiedDate = DateTime.Now;
                                db.Products.Add(pr);
                                db.SaveChanges();
                            }
                            else
                            {
                                data.Add("<ul>");
                                if (a.Name == "" || a.Name == null) data.Add("<li> name is required</li>");
                                if (a.Number == "" || a.Number == null) data.Add("<li> Address is required</li>");
                                data.Add("</ul>");
                                data.ToArray();
                                return Json(data, JsonRequestBehavior.AllowGet);
                            }
                        }
                        catch (DbEntityValidationException ex)
                        {
                            foreach (var entityValidationErrors in ex.EntityValidationErrors)
                            {
                                foreach (var validationError in entityValidationErrors.ValidationErrors)
                                {
                                    Response.Write("Property: " + validationError.PropertyName + " Error: " + validationError.ErrorMessage);
                                }
                            }
                        }
                    }
                    //deleting excel file from folder
                    if ((System.IO.File.Exists(pathToExcelFile)))
                    {
                        System.IO.File.Delete(pathToExcelFile);
                    }
                    return Json("success", JsonRequestBehavior.AllowGet);
                }
                else
                {
                    //alert message for invalid file format
                    data.Add("<ul>");
                    data.Add("<li>Only Excel file format is allowed</li>");
                    data.Add("</ul>");
                    data.ToArray();
                    return Json(data, JsonRequestBehavior.AllowGet);
                }
            }
            else
            {
                data.Add("<ul>");
                if (FileUpload == null) data.Add("<li>Please choose Excel file</li>");
                data.Add("</ul>");
                data.ToArray();
                return Json(data, JsonRequestBehavior.AllowGet);
            }
        }