将EntityFramework 4实体暴露为IList而不是IObjectSet [英] Exposing EntityFramework 4 entities as IList instead of IObjectSet

问题描述

我的实体框架4项目中有一个'客户'POCO实体。我想将我的客户实体作为通用列表而不是ObjectSet暴露给我的上层。

我有一个IUnitOfWork界面，如下所示：

  public interface IUnitOfWork 
 {
 string Save（）; 
 IList< Customer>客户{get; 
} 
  

在我的实体框架下DAL（实现上述界面）以下内容：

  public class EntityContainer：ObjectContext，IUnitOfWork 
 {
 private IObjectSet< Customer> _顾客; 
 
 public IList< Customer>客户
 {
 get 
 {
 if（_customers == null）
 {
 _customers = CreateObjectSet< Customer>（Customers）; 
} 
 return _customers.ToList< Customer>（）; 
} 
} 
} 
  

然而'CreateObjectSet客户）'行不行。每次我尝试添加一个新的客户什么都不发生。有趣的是，如果我恢复使用IObjectSet，那么代码可以工作。例如：

  public interface IUnitOfWork 
 {
 string Save（）; 
 IObjectSet< Contact>联系人{get; } 
} 
 
 
 public class EntityContainer：ObjectContext，IUnitOfWork 
 {
 private IObjectSet< Customer> _顾客; 
 
 public IObjectSet< Customer>客户
 {
 get 
 {
 if（_customers == null）
 {
 _customers = CreateObjectSet< Customer>（Customers）; 
} 
 return _customers; 
} 
} 
} 
  

IQueryable也可以，但是不能让IList工作，我不知道为什么。任何人有任何想法？

＃

更正原始问题。使用IQueryable不起作用，IEnumerable也不起作用。这是因为客户存储库需要提供添加和删除方法来添加/删除实体集合（在上面的示例中添加或删除客户实体）。 IQueryable或IEnumerable都不允许您添加或删除对象;相反，必须使用ICollection或IList。这让我回到原来的问题。我不想将我的集合作为ObjectSet暴露给存储库。我想使用一种不绑定到EntityFramework的类型，即我想使用通用列表。

有没有人有任何建议？我怀疑这样做有一个简单的方法，但是我对这个框架不够熟悉。

解决方案

_customers.ToList（）是罪魁祸首。 ToList执行查询并将该查询中的所有项目复制到新的集合对象中。此新的集合对象不提供ObjectSet具有的跟踪功能。

I have a 'Customer' POCO entity within my Entity Framework 4 project. I want to expose my Customer entities to my upper layers as a generic list rather than an ObjectSet.

I have an IUnitOfWork interface which looks as follows:

public interface IUnitOfWork
{
   string Save();
   IList<Customer> Customers { get; }
}

Down at my Entity Framework DAL (which implements the above interface) I have the following:

public class EntityContainer : ObjectContext, IUnitOfWork
{
    private IObjectSet<Customer> _customers;

    public IList<Customer> Customers 
    {
       get
       {
         if (_customers == null)
         {
             _customers = CreateObjectSet<Customer>("Customers");                    
         }
         return _customers.ToList<Customer>() ;
       }            
    }
}

However the 'CreateObjectSet("Customers")' line doesn't work. Every time I try to add a new 'Customer' nothing happens. Interestingly, if I revert to using an IObjectSet then the code works. For example:

public interface IUnitOfWork
{
    string Save();
    IObjectSet<Contact> Contacts { get; }
}


public class EntityContainer : ObjectContext, IUnitOfWork
{
    private IObjectSet<Customer> _customers;

    public IObjectSet<Customer> Customers 
    {
       get
       {
         if (_customers == null)
         {
             _customers = CreateObjectSet<Customer>("Customers");                    
         }
         return _customers;
       }            
    }
}

IQueryable also works, but I cannot get IList to work and I have no idea why. Anyone any ideas?

#

A correction to the original question. Using IQueryable doesn't work, nor does IEnumerable. This is because the Customer repository needs to provide 'Add' and 'Delete' methods to add/delete from the entity collection (add or remove customer entities in the above example). Neither IQueryable or IEnumerable allow you to add or remove objects; instead, an ICollection or IList must be used. This leaves me back at my original problem. I do not want to expose my collection to the repository as an ObjectSet. I want to use a type which is not tied to the EntityFramework i.e. - I want to use a generic list.

Has anyone any more suggestions? I suspect there's a straightforward way of doing this, but I'm not familiar enough with the framework to figure it out.

解决方案

_customers.ToList() is the culprit. ToList executes the query and copies all the items from that query into a new collection object. this new collection object does not provide the tracking capabilities that ObjectSet has.

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