public ActionResult Edit(ManageAlbumViewModel model, System.Web.HttpPostedFileBase file)
        {
            if (!ModelState.IsValid)
            {
                return(View(model));
            }
            if (file != null && file.ContentLength > 0)
            {
                var fileName = System.IO.Path.Combine(Request.MapPath("~/Content/Album/"), System.IO.Path.GetFileName(file.FileName));
                file.SaveAs(fileName);
                model.Cover = System.IO.Path.GetFileName(file.FileName);

                string oldCover = _db.tbl_Album.SingleOrDefault(a => a.album_Id == model.Id).album_Cover;
                if (model.Cover != oldCover && oldCover != "Album_1.jpg")
                {
                    ImageManager.Delete(Server.MapPath("~/Content/Album/" + oldCover));
                }
            }
            AlbumManager.Edit(model);
            ModelState.AddModelError("", "修改成功");
            return(RedirectToAction("Edit", new { id = model.Id }));
        }