c# - 如何在 F# 中实例化类及其属性

Question

遵循 C# 代码:

var body = new CustomerRequest
{
    Method = "CREDIT_CARD",
    CreditCard = new Creditcard
    {
        ExpirationMonth = "06",
        ExpirationYear = "2022",
        Number = "4012001037141112",
        Cvc = "123"
    }
};

我是F#的新手，我不能像C#那样实例化类，请看下面F#中的代码:

let body = CustomerRequest
(
    Method = "CREDIT_CARD"     // Help here
)

我无法将 C# 转换为 F#

Answer 1

如果您正在使用惯用的 F#，您可以使用 Records 对其进行建模而不是 classes .

你可以这样做:

type CreditCard = {
    ExpirationMonth: int;
    //More
}

type CustomerRequest = {
    Method: string;
    CreditCard: CreditCard;
}

let req = {
    Method = "Credit"
    CreditCard = {
        ExpirationMonth = 6
        //More
    }
}

编译器具有类型推断，这意味着它可以根据您在其中的字段猜测 req 是一个 CustomerRequest，对于 CreditCard 也是如此 - 如果确实需要，您可以提示类型。

如果你真的在课后——也许你必须与 C# 代码互操作，那么你会这样做:

type CreditCard2(expirationMonth:int) = 
    member this.ExpirationMonth = expirationMonth

type CustomerRequest2(method: string, creditCard: CreditCard2) = 
    member this.Method = method
    member this.CreditCard = creditCard

let req2 = CustomerRequest2 ("Credit", CreditCard2 (5))