使用包括-EF时,导航属性为null [英] Navigation property is null when using Include - EF
问题描述
我在打电话
Persons.Include(e => e.City)
Persons.Include(e => e.City)
在我的Web API的"Get()"方法中.
in "Get()" method in my web API.
城市"模型中的导航属性"ICollection人"返回null. 因此,当我使用"PostMan"获取值时,它将引发错误
The navigation property "ICollection persons" in "City" model return null. So when I use "PostMan" to get values it throw error
无法得到任何回应 连接到 http://localhost:13236/api/values 时出错.
Could not get any response There was an error connecting to http://localhost:13236/api/values.
我在GitHub上链接了一个测试项目: https://github.com/MajdAlbaho/SampleWebAPI
I linked a test project on GitHub : https://github.com/MajdAlbaho/SampleWebAPI
推荐答案
要启用延迟加载,必须将ICollection
属性标记为virtual
.
所以在您的示例中,而不是:
To enable lazy loading ICollection
property must be marked as virtual
.
so in your example, instead of:
public ICollection<Person> Persons { get; set; }
这样定义它:
public virtual ICollection<Person> Persons { get; set; }
本文可能会有所帮助:实体框架加载相关实体
This article may be helpful: Entity Framework Loading Related Entities
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