为实体框架生成的类添加数据注解 [英] Add data annotations to a class generated by entity framework

问题描述

我有以下实体框架生成的类:

I have the following class generated by entity framework:

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

我想将此设为必填字段

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

但是，因为这是生成的代码，所以会被清除.我无法想象创建分部类的方法，因为该属性是由生成的分部类定义的.如何以安全的方式定义约束?

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?

推荐答案

生成的类 ItemRequest 将始终是 partial 类.这允许您编写标有必要数据注释的第二个分部类.在您的情况下，部分类 ItemRequest 将如下所示:

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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