我在这里正确地使用了工作单元吗？(Entityi Framework 4 POCO)

Question

我发现了一些使用ef4创建工作单元的例子，我没有使用di/ioc，我想让事情变得简单，这是一个例子(90%的灵感)，我认为这是可以的，但既然我正在寻找一个从现在开始使用的模式，我想最后一次征求我的意见。

 public interface IUnitOfWork
 {
     void Save();
 }

public partial class TemplateEntities : ObjectContext, IUnitOfWork
{
    ....
    public void Save()
    {
        SaveChanges();
    }
}
public interface IUserRepository
{
    User GetUser(string username);
    string GetUserNameByEmail(string email);
    void AddUser(User userToAdd);
    void UpdateUser(User userToUpdate);
    void DeleteUser(User userToDelete);
    //some other
}
public class UserRepository : IUserRepository, IDisposable
{
    public TemplateEntities ctx;
    public UserRepository(IUnitOfWork unit)
    {
        ctx = unit as TemplateEntities;
    }
    public User GetUser(string username)
    {
        return (from u in ctx.Users
                where u.UserName == username
                select u).SingleOrDefault();
    }
    public string GetUserNameByEmail(string email)
    {
        return (from u in ctx.Users
                where u.Email == email
                select u.UserName).SingleOrDefault();
    }
    public void AddUser(User userToAdd)
    {
        ctx.Users.AddObject(userToAdd);
    }
    public void UpdateUser(User userToUpdate)
    {
        ctx.Users.Attach(userToUpdate);
        ctx.ObjectStateManager.ChangeObjectState(userToUpdate, System.Data.EntityState.Modified);
    }
    public void DeleteUser(User userToDelete)
    {
        ctx.Users.Attach(userToDelete);
        ctx.ObjectStateManager.ChangeObjectState(userToDelete, System.Data.EntityState.Deleted);
    }
    public void Dispose()
    {
        if (ctx != null)
            ctx.Dispose();
    }
}

最后

    public class BogusMembership : MembershipProvider
    {
        public MembershipCreateStatus CreateUser(string username, string password, string email, bool autoemail, string fullname)
        {
            IUnitOfWork ctx = new TemplateEntities();
            using (UserRepository rep = new UserRepository(ctx))
            {
                using (TransactionScope tran = new TransactionScope())
                {
                    if (rep.GetUser(username) != null)
                        return MembershipCreateStatus.DuplicateUserName;
                    if (requiresUniqueEmail && !String.IsNullOrEmpty(rep.GetUserNameByEmail(email)))
                        return MembershipCreateStatus.DuplicateEmail;
                    User userToCreate = new User
                    {
                        UserName = username,
                        PassWord = EncodePassword(password),
                        FullName = fullname,
                        Email = email,
                        AutoEmail = autoemail
                    };
                    try
                    {
                        rep.AddUser(userToCreate);
                        ctx.Save();
                        tran.Complete();
                        return MembershipCreateStatus.Success;
                    }
                    catch
                    {
                        return MembershipCreateStatus.UserRejected;
                    }
                }
            }
        }
    }

在去掉IUnitOfWork和IDisposal之后，CreateUser看起来像这样：

        public MembershipCreateStatus CreateUser(string username, string password, string email, bool autoemail, string fullname)
        {
            using (TransactionScope tran = new TransactionScope())
            {
                using (TemplateEntities ctx = new TemplateEntities())
                {
                    UserRepository rep = new UserRepository(ctx);
                    //OtherRepository rep2 = new OtherRepository(ctx);
                    if (rep.GetUser(username) != null)
                        return MembershipCreateStatus.DuplicateUserName;
                    if (requiresUniqueEmail && !String.IsNullOrEmpty(rep.GetUserNameByEmail(email)))
                        return MembershipCreateStatus.DuplicateEmail;
                    User userToCreate = new User
                    {
                        UserName = username,
                        PassWord = EncodePassword(password),
                        FullName = fullname,
                        Email = email,
                        AutoEmail = autoemail
                    };
                    try
                    {
                        rep.AddUser(userToCreate);
                        ctx.SaveChanges();
                        tran.Complete();
                        return MembershipCreateStatus.Success;
                    }
                    catch
                    {
                        return MembershipCreateStatus.UserRejected;
                    }
                }
            }
        }

Answer 1

这看起来基本上没问题。不过，还是有一些建议：

• 您不应该让存储库处理TemplateEntities。这样做的原因是，当您在一个事务中需要两个存储库时，就会出现问题。您应将处置TemplateEntities的责任移至与TransactionScope;
• The TransactionScope应移至更高级别相同的级别。最好是在TransactionScope;
• You中实例化TemplateEntities，如果它不包含功能，则不必创建Save包装器。如果您在void SaveChanges()接口上指定IUnitOfWork，这将拾取public TemplateEntities Ctx { get; private set; };
• You的void SaveChanges()我不会使用string GetUserNameByEmail(...)，而是User GetUserByEmail(...)，因为这样做也可以满足您的需求，并且您的优势在于，当您以后需要时，User GetUserByEmail(...);
• You可能会考虑将ctx设置为私有的，或者至少像public TemplateEntities Ctx { get; private set; }；
• You这样的私有设置器可以使用下面的方法创建一个抽象存储库。从长远来看，这将为您节省大量枯燥的输入工作：

-

public interface IRepository<TEntity>
{
    void Delete(TEntity entity);

    /* ... */
}

public abstract class AbstractRepository<TEntity> : IRepository<TEntity>
{
    public TemplateEntities ctx;

    public AbstractRepository(IUnitOfWork unit)
    {
        ctx = unit as TemplateEntities;
    }

    protected abstract ObjectSet<TEntity> Entites { get; }

    public virtual void Delete(TEntity entity)
    {
        Entities.Attach(entity);
        ctx.ObjectStateManager.ChangeObjectState(entity, System.Data.EntityState.Deleted);
    }

    /* ... */
}

public interface IUserRepository : IRepository<User>
{
    User GetUser(string username);

    /* ... */
}

public class UserRepository : AbstractRepository<User>, IUserRepository
{
    public UserRepository(IUnitOfWork unit)
        : base(unit)
    {
    }

    protected override ObjectSet<User> Entites
    {
        get { return ctx.Users; }
    }

    public User GetUser(string username)
    {
        return (from u in ctx.Users
                where u.UserName == username
                select u).SingleOrDefault();
    }

    /* ... */
}