gistfile1.txt

if (ModelState.IsValid)
                {
                    if (returnDetails != null)
                    {
                        returnDetails.ReturnDate = DateTime.Now;
                    }
                    returnDetails.Name = currentUser;
                    db.returnDetails.Add(returnDetails);
                    db.SaveChanges();
                    order.ReturnId = returnDetails.ReturnId;
                    db.SaveChanges();
                    return RedirectToAction("Index");
                }

                return View(returnDetails);
            }