单击按钮打印Observable的结果？

Question

无论如何从按钮点击打印当前观察的结果？

示例：

button.Click.Add(fun _ ->  x |>Observable.subscribe (fun x -> printfn "%A" x))

Answer 1

您可以在ref：

中存储订阅获得的最后一个值

let curX = ref None

let subscription = x |> Observable.subscribe (fun v -> 
    lock curX (fun () -> curX := Some v)
)

button.Click.Add (fun _ ->
    match lock curX (fun () -> !curX) with
    | Some v -> printfn "X yielded \"%A\"." v
    | None -> printfn "X yielded nothing."
)