更新W/ ef4 repo&MVC2的问题 - 无法更新多个对数图
-
16-10-2019 - |
题
我似乎无法成功地使用EF4在MVC2中成功更新一个多对多的图。我认为最简单的事情是要清除()整个图形,调用savechanges(),然后在末尾再次重建拨打savechanges()的图形,但它不起作用。我所有的其他属性 是 但是,工作。首先,我的行动方法:
public ActionResult EditReview(int id)
{
var game = _gameRepository.GetGame(id);
var genres = _gameRepository.AllGenres();
var platforms = _gameRepository.AllPlatforms();
var model = new AdminGameViewModel { GameData = game, AllGenres = genres, AllPlatforms = platforms };
return View(model);
}
//
// POST: /Admin/EditReview/5
[HttpPost]
public ActionResult EditReview([Bind(Prefix="GameData")]Game existingGame, int[] PlatformIDs)
{
try
{
_gameRepository.ValidateGame(existingGame, PlatformIDs);
}
catch(RulesException ex)
{
ex.CopyTo(ModelState);
ex.CopyTo(ModelState, "GameData");
}
if (ModelState.IsValid)
{
return RedirectToAction("Index");
}
else
{
var genres = _gameRepository.AllGenres();
var platforms = _gameRepository.AllPlatforms();
var model = new AdminGameViewModel { GameData = existingGame, AllGenres = genres, AllPlatforms = platforms };
return View(model);
}
}
存储库本身(有效策略和savegame是相关方法):
namespace HandiGamer.Domain.Concrete
{
public class HGGameRepository : IGameRepository
{
private HGEntities _siteDB = new HGEntities();
public List<Game> Games
{
get { return _siteDB.Games.ToList(); }
}
public void ValidateGame(Game game, int[] PlatformIDs)
{
var errors = new RulesException<Game>();
if (string.IsNullOrEmpty(game.GameTitle))
{
errors.ErrorFor(x => x.GameTitle, "A game must have a title");
}
if (string.IsNullOrEmpty(game.ReviewText))
{
errors.ErrorFor(x => x.ReviewText, "A review must be written");
}
if (game.ReviewScore <= 0 || game.ReviewScore > 5)
{
errors.ErrorFor(x => x.ReviewScore, "A game must have a review score, and the score must be between 1 and 5");
}
if (string.IsNullOrEmpty(game.Pros))
{
errors.ErrorFor(x => x.Pros, "Each game review must have a list of pros");
}
if (string.IsNullOrEmpty(game.Cons))
{
errors.ErrorFor(x => x.Cons, "Each game review must have a list of cons");
}
if (PlatformIDs == null || PlatformIDs.Length == 0)
{
errors.ErrorForModel("A game must belong to at least one platform");
}
if (game.GenreID == 0)
{
errors.ErrorFor(x => x.GenreID, "A game must be associated with a genre");
}
if (errors.Errors.Any())
{
throw errors;
}
else
{
SaveGame(game, PlatformIDs);
}
}
public void SaveGame(Game game, int[] PlatformIDs)
{
_siteDB.Games.Attach(game);
if (game.GameID > 0)
{
_siteDB.ObjectStateManager.ChangeObjectState(game, System.Data.EntityState.Modified);
game.Platforms.Clear();
}
else
{
_siteDB.ObjectStateManager.ChangeObjectState(game, System.Data.EntityState.Added);
}
foreach (int id in PlatformIDs)
{
Platform plat = _siteDB.Platforms.Single(pl => pl.PlatformID == id);
game.Platforms.Add(plat);
}
game.LastModified = DateTime.Now;
_siteDB.SaveChanges();
}
public Game GetGame(int id)
{
return _siteDB.Games.Include("Genre").Include("Platforms").SingleOrDefault(g => g.GameID == id);
}
public IEnumerable<Game> GetGame(string title)
{
return _siteDB.Games.Include("Genre").Include("Platforms").Where(g => g.GameTitle.StartsWith(title)).AsEnumerable<Game>();
}
public List<Game> GetGamesByGenre(int id)
{
return _siteDB.Games.Where(g => g.GenreID == id).ToList();
}
public List<Game> GetGamesByGenre(string genre)
{
return _siteDB.Games.Where(g => g.Genre.Name == genre).ToList();
}
public List<Game> GetGamesByPlatform(int id)
{
return _siteDB.Games.Where(g => g.Platforms.Any(p => p.PlatformID == id)).ToList();
}
public List<Game> GetGamesByPlatform(string platform)
{
return _siteDB.Games.Where(g => g.Platforms.Any(p => p.Name == platform)).ToList();
}
public List<Genre> AllGenres()
{
return _siteDB.Genres.OrderBy(g => g.Name).ToList();
}
public List<Platform> AllPlatforms()
{
return _siteDB.Platforms.OrderBy(p => p.PlatformID).ToList();
}
}
}
我很难过。
解决方案
凯文(Kevin),哦,这有点复杂,迫使您回到EFV1模式,因为使用M:m,您没有外国钥匙可以依靠,并且您被对象所困。
添加游戏时,您确实希望添加关系(即加入表中的一行),但您不希望添加平台,因为它只是一个参考。
我实际上还没有这样做,但是我认为如果您可以将其分开,然后一旦添加并添加游戏后,就会更容易重建平台集合。否则,如果添加了整个图,则将添加所有内容。
EF的问题是,如果您附上游戏,您也会得到相关的内容。可能会有一个更干净的模式,但我的想法是将平台从游戏中分离,将游戏连接到上下文,并将其标记为添加。然后,我将平台附加到上下文。他们将“不变”。然后将它们添加到游戏中。平台集合。平台仍将保持不变,但是 : 将被理解。
您可能已经尝试过。当我继续前进时,我必须自己做,并观察一切的实体状态。关键是EF需要跟踪 关系 已经添加了新的(这是新的(并将在加入表中添加)),但了解平台并不新。
Hth Julie
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