外国财产中[必需]的不同含义

Question

在Id上使用必填字段的差异是什么

[Required]
public int? UserId {get; set;}

[ForeignKey("UserId")]
public User User {get; set;}

导航属性或

public int? UserId {get; set;}

[Required]
[ForeignKey("UserId")]
public User User {get; set;}

两者：

[Required]
public int? UserId {get; set;}

[Required]
[ForeignKey("UserId")]
public User User {get; set;}

Answer 1

在这里，只需阅读它，它就会帮助你：

https://docs.microsoft.com/en-us/dotnet/articles/csharp/programming-guide/classes-and-structs/fields