从 WaitHandle.Wait 构造任务

我选择返回Task<T> and Task从我的对象方法中可以通过 GUI 轻松使用。有些方法只是等待其他类型的等待句柄的互斥体。有没有办法构建Task from WaitHandle.Wait()这样我就不必为此阻塞一个treadpool线程。

有一种方法可以做到这一点：您可以使用订阅 WaitHandleThreadPool.RegisterWaitForSingleObject方法并通过包装它任务完成源 class:

public static class WaitHandleEx
{
    public static Task ToTask(this WaitHandle waitHandle)
    {
        var tcs = new TaskCompletionSource<object>();

        // Registering callback to wait till WaitHandle changes its state

        ThreadPool.RegisterWaitForSingleObject(
            waitObject: waitHandle,
            callBack:(o, timeout) => { tcs.SetResult(null); }, 
            state: null, 
            timeout: TimeSpan.MaxValue, 
            executeOnlyOnce: true);

        return tcs.Task;
    }
}

Usage:

WaitHandle wh = new AutoResetEvent(true);
var task = wh.ToTask();
task.Wait();