点击按钮打印Observable的结果

Question

是否可以通过单击按钮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

您可以将订阅获得的最后一个值存储在ref:中

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."
)