兩種接口的F＃顯式接口方法

Question

處理這種情況的正確方法是什么。 我的F＃類DogTree中有一個方法應該滿足為兩個接口實現Bark（）方法的要求。

type ITree =
    interface
        abstract Bark : unit -> unit
        abstract Grow : unit -> unit
    end

type IDog =
    interface
        abstract Bark : unit -> unit
        abstract ChaseCar : unit -> unit
    end

type TreeDog = 
   // so the "and" syntax below doesn't work - what is the correct way to handle?
   interface IDog and ITree with
      member this.Bark() = printfn "Bark" 

Answer 1

您可以委派一個常見的實現：

type TreeDog = 
  interface IDog with
    member this.Bark() = printfn "Bark" 
  interface ITree with
    member this.Bark() = (this :> IDog).Bark()

或者，更合適：

type TreeDog = 
  member this.Bark() = printfn "Bark"
  interface IDog with
    member this.Bark() = this.Bark() 
  interface ITree with
    member this.Bark() = this.Bark()

（請注意，這在名為Bark的類中定義了一個額外的方法，該方法用作兩個接口的實現。）

如果在類中聲明主構造函數，則可以使用它：

type TreeDog() = // primary constructor
  let bark() = printfn "Bark" // this member is private
  interface IDog with
    member this.Bark() = bark()
  interface ITree with
    member this.Bark() = bark()

Answer 2

這相當優雅

type TreeDog() = 
  let bark() = printfn "Bark" 
  interface IDog with
    member this.Bark() = bark()
  interface ITree with
    member this.Bark() = bark()