json - F#:如何将 Json.NET [JsonConstructor] 属性应用于主构造函数？

Question

我正在尝试在 F# 中做一些事情，比如 JsonConstructorAttribute Json.NET documentation 中的示例:

public class User
{
    public string UserName { get; private set; }
    public bool Enabled { get; private set; }

    public User()
    {
    }

    [JsonConstructor]
    public User(string userName, bool enabled)
    {
        UserName = userName;
        Enabled = enabled;
    }
}

F# 中的模拟似乎类似于以下内容，但我在放置 [<JsonConstructor>] 时遇到错误:

[<JsonConstructor>] // ERROR! (see below)
type User (userName : string, enabled : bool) =
    member this.UserName = userName
    member this.Enabled = enabled

错误是

This attribute is not valid for use on this language element

那么，我如何用 [<JsonConstructor>] 装饰主构造函数？ ?

Answer 1

事实证明这很容易。通过放置 [<JsonConstructor>] 来定位主构造函数就在主构造函数的参数列表之前:

type User [<JsonConstructor>] (userName : string, enabled : bool) =
    member this.UserName = userName
    member this.Enabled = enabled