将数据注释添加到由实体框架生成的类中 [英] Add data annotations to a class generated by entity framework

问题描述

  public partial class ItemRequest 
 {
 public int RequestId {get;组; } 
 // ... 
  

我想让这个必填字段

  [必需] 
 public int RequestId {get; set; } 
  

但是，因为这是生成的代码，所以将被清除。我无法想象创建一个部分类的方法，因为属性是由生成的部分类定义的。

解决方案

生成的类 ItemRequest 将永远是一个 partial 类。这允许您编写一个第二个部分类，其中标有必要的数据注释。在你的情况下，部分类 ItemRequest 将如下所示：

  using System.ComponentModel; 
使用System.ComponentModel.DataAnnotations; 
 
 //确保命名空间等于其他部分类ItemRequest 
命名空间MvcApplication1.Models 
 {
 [MetadataType（typeof（ItemRequestMetaData））] 
 public partial class ItemRequest 
 {
} 
 
 public class ItemRequestMetaData 
 {
 [必需] 
 public int RequestId {get; set ;} 
 
 // ... 
} 
} 
  

I have the following class generated by entity framework:

public partial class ItemRequest
{
    public int RequestId { get; set; }
    //...

I would like to make this a required field

[Required]
public int RequestId { get;set; }

However, because this is generated code this will get wiped out. I can't imagine a way to create a partial class because the property is defined by the generated partial class. How can I define the constraint in a safe way?

解决方案

The generated class ItemRequest will always be a partial class. This allows you to write a second partial class which is marked with the necessary data annotations. In your case the partial class ItemRequest would look like this:

using System.ComponentModel;
using System.ComponentModel.DataAnnotations;

//make sure the namespace is equal to the other partial class ItemRequest
namespace MvcApplication1.Models 
{
    [MetadataType(typeof(ItemRequestMetaData))]
    public partial class ItemRequest
    {
    }

    public class ItemRequestMetaData
    {
        [Required]
        public int RequestId {get;set;}

        //...
    }
}

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