忽略Entity Framework 4.1代码中的类属性 [英] Ignoring a class property in Entity Framework 4.1 Code First

问题描述

我的理解是，在目前在CTP中的EF 5之前， [NotMapped] 属性不可用，所以我们无法在生产中使用它。

My understanding is that the [NotMapped] attribute is not available until EF 5 which is currently in CTP so we cannot use it in production.

如何将EF 4.1中的属性标记为忽略？

How can I mark properties in EF 4.1 to be ignored?

更新：我注意到其他奇怪的东西。我得到 [NotMapped] 属性工作，但由于某些原因，EF 4.1仍然在数据库中创建一个名为Disposed的列，即使 public bool Disposed {get;私人集合} 标有 [NotMapped] 。当然，该类实现了 IDisposeable ，但是我看不出应该如何。任何想法？

UPDATE: I noticed something else strange. I got the [NotMapped] attribute to work but for some reason, EF 4.1 still creates a column named Disposed in the database even though the public bool Disposed { get; private set; } is marked with [NotMapped]. The class implements IDisposeable of course but I don't see how that should matter. Any thoughts?

推荐答案

您可以使用 NotMapped 注释来指示代码 - 首先排除特定属性

You can use the NotMapped Annotation to instruct Code-First to exclude a particular property

public class Customer
{
    public int CustomerID { set; get; }
    public string FirstName { set; get; } 
    public string LastName{ set; get; } 
    [NotMapped]
    public int Age { set; get; }
}

[NotMapped] 属性包含在 System.ComponentModel.DataAnnotations 命名空间中。

[NotMapped] attribute is included in the System.ComponentModel.DataAnnotationsnamespace.

您也可以使用流利的API 覆盖在 DBContext 类中的OnModelCreating 函数类：

You can alternatively do this with Fluent API overriding OnModelCreating function in your DBContext class:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
   modelBuilder.Entity<Customer>().Ignore(t => t.LastName);
   base.OnModelCreating(modelBuilder);
}

http://msdn.microsoft.com/en-us/library/hh295847（v = vs103）.aspx

我检查的版本是 EF 4.3 ，这是您使用NuGet时最新的稳定版本。

The version I checked is EF 4.3, which is the latest stable version available when you use NuGet.

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