F# 联合成员的 Enum.GetName 等效项是什么? [英] What is the Enum.GetName equivalent for F# union member?

问题描述

我想为 F# 受歧视的联合成员获得等效的 Enum.GetName.调用 ToString() 给了我 TypeName+MemberName，这不是我想要的.当然，我可以将它子串起来，但是它安全吗?或者也许有更好的方法?

I want to get the equivalent of Enum.GetName for an F# discriminated union member. Calling ToString() gives me TypeName+MemberName, which isn't exactly what I want. I could substring it, of course, but is it safe? Or perhaps there's a better way?

推荐答案

您需要使用 Microsoft.FSharp.Reflection 命名空间中的类，因此:

You need to use the classes in the Microsoft.FSharp.Reflection namespace so:

open Microsoft.FSharp.Reflection

///Returns the case name of the object with union type 'ty.
let GetUnionCaseName (x:'a) = 
    match FSharpValue.GetUnionFields(x, typeof<'a>) with
    | case, _ -> case.Name  

///Returns the case names of union type 'ty.
let GetUnionCaseNames <'ty> () = 
    FSharpType.GetUnionCases(typeof<'ty>) |> Array.map (fun info -> info.Name)

// Example
type Beverage =
    | Coffee
    | Tea

let t = Tea
> val t : Beverage = Tea

GetUnionCaseName(t)
> val it : string = "Tea"

GetUnionCaseNames<Beverage>()
> val it : string array = [|"Coffee"; "Tea"|]

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