Question

要解释我认为最好用一个例子：

type myRec = {x: string}
type myRec2 = {x: string}
let x = {x = "hello"}
let y(a: myRec) = a.x
y(x);;

  y(x);;
   --^

error FS0001: This expression was expected to have type
    myRec    
but here has type
    myRec2

那么，如果x和myRec具有相同的签名，我如何强制myRec拥有myRec2类型？

Answer 1

let x = { myRec.x = "hello" }
// or
let x:myRec = { x = "hello" }
// or
let x = { x = "hello" } : myRec

the documentation中提供了更多详细信息和示例。

_{编辑：注释中的备选方案。}

Answer 2

是的，你可以：

let x = { new myRec() with x = "hello" }

使用and分配更多字段：

let x = { new myRec3() with x = "hello" and y = "bye" }

在进行作业时是否可以在F＃中强制记录类型？

2 个答案: