EF Code First Lazy加载不工作 [英] EF Code First Lazy loading Not Working

问题描述

我正在使用EF6代码，但似乎无法懒惰加载工作。渴望加载工作正常。我有以下课程：

  public class商家：用户
 {
 ... 
 
 public virtual ICollection< MerchantLocation> MerchantLocations {get;组; 
} 
 
 public class MerchantLocation：BaseEntity 
 {
 ... 
 
 public int MerchantId {get;组; } 
 public virtual Merchant {get;组; } 
} 
 
 public class User：BaseEntity 
 {
 ... 
} 
 
 public class BaseEntity 
 {
 ... 
 
 public int Id {get;组; } 
} 
  

我通过以下代码测试我的懒惰加载的位置（失败）：$ {

$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ b var merchant = context.Users.OfType< Merchant> .First（）;
merchant.MerchantLocations.ShouldNotBeNull（）; //失败
}
}

但是，希望加载工作正常： p $

  public void Test_Eager_Loading（）{
 using（var context = new MyDbContext（））{
 var merchant = context.Users.OfType<商家GT; .INCLUDE（ MerchantLocations）第一（）; 
 merchant.MerchantLocations.ShouldNotBeNull（）; //通过
} 
} 
  

MerchantLocations 被标记为 public virtual ，所以我不知道是什么问题。我还在我的 DbContext 构造函数中添加了以下内容：

 配置。 LazyLoadingEnabled = true; 
 Configuration.ProxyCreationEnabled = true; 
  

编辑：我也注意到商家在上述测试中返回的对象不是EF代理。这是一个简单的商家。我怀疑这是导致这个问题。

解决方案

我意识到问题是商家类不符合代理要求代。具体来说，我需要添加一个受保护的无参数构造函数。我只有一个私人的。

I am using code first with EF6 but cannot seem to get lazy loading to work. Eager loading is working fine. I have the following classes:

public class Merchant : User
{
    ...

    public virtual ICollection<MerchantLocation> MerchantLocations { get; set; }
}

public class MerchantLocation : BaseEntity
{
    ...

    public int MerchantId { get; set; }
    public virtual Merchant Merchant { get; set; }       
}

public class User : BaseEntity
{
    ...
}

public class BaseEntity
{
    ...

    public int Id { get; set; }
}

I test my lazy loading of the locations via the following code (which fails):

public void Test_Lazy_Loading() {
    using (var context = new MyDbContext()) {
        var merchant = context.Users.OfType<Merchant>.First();
        merchant.MerchantLocations.ShouldNotBeNull(); // fails
    }
}

However eager loading works fine:

public void Test_Eager_Loading() {
    using (var context = new MyDbContext()) {
        var merchant = context.Users.OfType<Merchant>.Include("MerchantLocations").First();
        merchant.MerchantLocations.ShouldNotBeNull(); // passes
    }
}

MerchantLocations is marked as public virtual so I'm not sure what the problem is. I have also added the following in my DbContext constructor:

Configuration.LazyLoadingEnabled = true;
Configuration.ProxyCreationEnabled = true;

edit: I have also noticed that the merchant object being returned in the above tests is not an EF proxy. It is a plain Merchant. I suspect that this is causing the problem.

解决方案

I realized that the problem was that the Merchant class did not meet requirements for proxy generation. Specifically, I needed to add a protected parameterless constructor. I only had a private one.

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