Question

我最近发现（见this page末尾附近）可以在初始化时设置属性，如下面的最后一行所示。这非常简洁：

type Account() =
    let mutable balance = 0.0
    member this.Balance
       with get() = balance
       and set(value) = balance <- value

let account1 = new Account(Balance = 1543.33)

有没有办法以类似简洁的方式设置子属性（即属性的属性），而不会完全覆盖它们？

例如，我想写下这些内容：

type Person() =
    let mutable name = ""
    let mutable someProperty = ""
    member this.Name
       with get() = name
       and set(value) = name <- value
    member this.SomeProperty
       with get() = someProperty
       and set(value) = someProperty <- value

type Account() =
    let mutable balance = 0.0
    let mutable person = new Person(SomeProperty = "created by an account")
    member this.Person
       with get() = person
       and set(value) = person <- value
    member this.Balance
       with get() = balance
       and set(value) = balance <- value

let account1 = new Account(Balance = 1543.33, Person.Name = "John Smith")

但是，最后一行产生的编译错误并不完全合理：Named arguments must appear after all other arguments。

请注意，这实际上是与C＃库互操作，所以我不一定要为该属性构造一个新对象。如果可能的话，我不会在F＃中使用这样的可变属性。

Answer 1

是的，你可以这样做。

尝试以下方法：

let account1 = new Account(Balance = 1543.33, Person = Person(Name = "John Smith"))

修改海报后的修改问题：如果我正确遵循，我仍然不能100％确定，但解决方案可能如下。它感觉不是特别有用，但鉴于这是为了与C＃类交互，我不认为这是一个问题：

type Account() =
let mutable balance = 0.0
static let mutable person = new Person(SomeProperty = "created by an account")
member this.Person
   with get() = person
   and set(value) = person <- value
member this.Balance
   with get() = balance
   and set(value) = balance <- value
static member GetPerson = person


let account2 = new Account(Balance = 1543.33, Person = Person (Name = "John Smith", SomeProperty = Account.GetPerson.SomeProperty))

是否可以在F＃中初始化时设置子属性？

1 个答案: