[英]Custom attribute on record fields F#
我正在嘗試在記錄中聲明自定義屬性並嘗試讀取它。 它似乎不起作用。 請指教。
// Custom Attribute for record fields
[<AttributeUsage(AttributeTargets.Field)>]
type Name(x: string) =
inherit Attribute()
member _.value = x
// Record type
type User =
{ [<Name("id")>]
Id: int
[<Name("email")>]
Email: string
[<Name("organization_id")>]
OrganizationId: option<string> }
// Trying to read the attribute. This is not working. I am getting <null> here.
let parse () =
FSharpType.GetRecordFields(typeof<User>)
|> Array.map (fun p -> p.Name, p.GetCustomAttribute(typeof<Name>, false))
|> Array.iter (fun (t, a) -> printfn "%s : %A" t a)
下面的代碼解決了這個問題。 有關更詳細的答案,請參閱此鏈接。
// Changing to property instead of field
[<AttributeUsage(AttributeTargets.Property)>]
type Name(x: string) =
inherit Attribute()
member _.value = x
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