enums - F# 中枚举的注释

Question

我在 F# 中有一个枚举:

type Gender = Undisclosed = 0 | Male = 1 | Female = 2

等效的 C# 代码将是

public enum Gender
{
    Undisclosed,
    Male,
    Female
}

事实上，在C#中，我可以更上一层楼。在 cshtml 的下拉菜单中使用性别页面，我可以这样做:

public enum Gender
{
    [Display(ResourceType = typeof(LocalisedStrings), Name = "GenderUndisclosed")] Undisclosed,
    [Display(ResourceType = typeof(LocalisedStrings), Name = "GenderMale")] Male,
    [Display(ResourceType = typeof(LocalisedStrings), Name = "GenderFemale")] Female
}

不幸的是，如果我尝试向 F# 枚举成员添加类似的注释，F# 编译器会说“此处不允许使用属性”。有没有解决的办法？如果可能的话，我想避免创建重复的类并执行 Automapper voodoo。

Answer 1

您需要一个 |在属性之前。

// Doesn't compile. "Attributes are not allowed here"
type Foo = [<Bar>] Baz = 0

// Compiles.
type Foo = | [<Bar>] Baz = 0

在你的情况下，这将是:

type Gender = 
    | [<Display(ResourceType = typeof<LocalisedStrings>, Name = "GenderUndisclosed")>] Undisclosed = 0
    | [<Display(ResourceType = typeof<LocalisedStrings>, Name = "GenderMale")>] Male = 1
    | [<Display(ResourceType = typeof<LocalisedStrings>, Name = "GenderFemale")>] Female = 2