Question

我有一个实体框架代码头等舱（POCO）：

class Contract : IMyContract
{
   ...
}

interface IMyContract
{
   public int DateSigned{get;}
}

为什么在客户修改合同时，我无法以这种方式拦截上下文更改操作：

void context_SavingChanges(object sender, EventArgs e)
{

    foreach (ObjectStateEntry entry in
        ((ObjectContext)sender).ObjectStateManager.GetObjectStateEntries(
        EntityState.Added | EntityState.Modified | EntityState.Deleted))
    {

        IMyContract myContract = entry.Entity as IMyContract;
        if(myContract != null) 
        { 
           ...
        }
    }
}

Answer 1

您提到了代码优先，但同时您正在处理ObjectContext事件并将发件人转发给ObjectContext

请改为尝试：

public class MyContext : DbContext
{
    private static EntityState[] states = new EntityState[] 
        { 
             EntityState.Added,
             EntityState.Modified,
             EntityState.Deleted,
        };

    ...

    public override int SaveChanges()
    {
        // If Entires<IMyContract> doesn't work use Entries() and check type 
        // inside the loop
        foreach(var entry in ChangeTracker.Entries<IMyContract>()
                                          .Where(e => states.Contains(e.State))
        {
           ...
        }
    }
}

使用带有Entity Framework Code First的接口/抽象类

1 个答案: