在 F# 中同时等待多个事件的任何事件

问题描述

在 F# 中，我知道如何使用 Async 异步等待一个事件.AwaitEvent:

In F# I know how to wait asynchronously for one event using Async.AwaitEvent:

let test = async {
  let! move = Async.AwaitEvent(form.MouseMove)
  ...handle move... }

假设我想等待 MouseMove 或 KeyDown 事件.我想要这样的东西:

Suppose I want to wait for either the MouseMove or the KeyDown event. I'd like to have something like this:

let! moveOrKeyDown = Async.AwaitEvent(form.MouseMove, form.KeyDown)

此功能不存在，但还有其他方法吗?

This function doesn't exist but is there another way to do this?

推荐答案

let ignoreEvent e = Event.map ignore e

let merged = Event.merge (ignoreEvent f.KeyDown) (ignoreEvent f.MouseMove)
Async.AwaitEvent merged

另一个保留原始类型的版本

another version that preserves original types

let merged = Event.merge (f.KeyDown |> Event.map Choice1Of2) (f.MouseMove |> Event.map Choice2Of2)
Async.AwaitEvent merged

EDIT 2:根据 Tomas Petricek

let e1 = f.KeyDown |> Observable.map Choice1Of2
let e2 = f.MouseMove |> Observable.map Choice2Of2
let! evt = Observable.merge e1 e2 |> Async.AwaitObservable

AwaitObservable 原语可以从这里获取(Tomas Petricek 的Silverlight 中的反应式演示").

AwaitObservable primitive can be taken from here ('Reactive demos in Silverlight' by Tomas Petricek).

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