使用实体框架 6 的存储库模式更新记录 [英] Updating records using a Repository Pattern with Entity Framework 6

问题描述

我正在编写一个简单的博客应用程序，并尝试在我的通用存储库模式中建立 CRUD 操作，但我的更新方法出现错误:

I'm writing a simple blog application and trying to establish CRUD operations in my generic repository pattern but I'm getting an error on my update method that says:

'System.Data.Entity.DbSet' 不包含定义'Entry' 和没有扩展方法 'Entry' 接受第一个参数可以找到类型System.Data.Entity.DbSet"(您是否缺少使用指令还是程序集引用?)

'System.Data.Entity.DbSet' does not contain a definition for 'Entry' and no extension method 'Entry' accepting a first argument of type 'System.Data.Entity.DbSet' could be found (are you missing a using directive or an assembly reference?)

我关注了一篇解释的帖子通过在 DbContext 上添加额外的间接级别来伪造"Entry().然而，在 MVC 5 中，我们继承自:IdentityDbContext 而不是 DbContext.我确实尝试实施作者的修复，但错误仍然存​​在.

I followed a post that explained how to 'fake' Entry() by adding additional level of indirection over DbContext. However in MVC 5 we're inheriting from: IdentityDbContext and not DbContext. I did try implementing the authors fix but the error persists.

如何使用 IdentityDbContext 向实体框架 6 中的存储库添加更新方法?如果我们不应该这样做，那么我如何使用这种模式更新记录?

How can I add an update method to my repository in Entity Framework 6 using IdentityDbContext? If we aren't supposed to do it this way then how do I update a record with this pattern?

我应该注意到所有其他方法都按预期工作.

I should note that all other the other methods work as expected.

我的通用存储库:

public class BlogEngineRepository<T> : IRepository<T> where T : class
    {
        protected DbSet<T> DbSet;

        public BlogEngineRepository(DbContext dataContext)
        {
            DbSet = dataContext.Set<T>();
        }

        #region IRepository<T> Members

        public void Insert(T entity)
        {
            DbSet.Add(entity);
        }

        public void Delete(T entity)
        {
            DbSet.Remove(entity);
        }

        public void Update(T entity)
        { 

           DbSet.Entry(entity).State = System.Data.Entity.EntityState.Modified;

        }

        public IQueryable<T> SearchFor(Expression<Func<T, bool>> predicate)
        {
            return DbSet.Where(predicate);
        }

        public IQueryable<T> GetAll()
        {
            return DbSet;
        }

        public T GetById(int id)
        {
            return DbSet.Find(id);
        }

        #endregion
    }

推荐答案

更新应该看起来像(扩展 Dan Beaulieu 的答案) :

Update should look like (expanding on Dan Beaulieu's answer) :

[HttpPost]
[ValidateAntiForgeryToken]
[ValidateInput(false)]
public ActionResult Edit([Bind(Include = "Id,Title,IntroText,Body,Modified,Author")] Post post)
{
    using (UnitOfWork uwork = new UnitOfWork())
    {
        post.Modified = DateTime.Now;
        uwork.PostRepository.Update(post);

        uwork.Commit();

        return RedirectToAction("Index");
    }
}

RepositoryPattern 看起来像这样:

public class BlogEngineRepository<T> : IRepository<T> where T : class
{
  public BlogEngineRepository(DbContext dataContext)
  {
    DbSet = dataContext.Set<T>();
    Context = dataContext;
  }

  public T Update(T entity)
  {
     DbSet.Attach(entity);
     var entry = Context.Entry(entity);
     entry.State = System.Data.EntityState.Modified;
  }
}

您可以查看对高效的答案的完整解释更新实体列表的方式，了解有关更新详情的更多信息.

You can view a full explaination to the answer for Efficient way of updating list of entities for more information on the details of just an update.

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