记录字段上的自定义属性 F#

Question

I am trying to declare a custom attribute in a record and trying to read it. It seems to be not working. Please advise.

// 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)

Answer 1

The below code fixes the problem. For more detailed answer, refer this link .

// Changing to property instead of field
[<AttributeUsage(AttributeTargets.Property)>]
type Name(x: string) =
    inherit Attribute()
    member _.value = x