阻止直到事件完成

Question

在异步事件完成之前,您如何阻止？

这是一种通过在事件处理程序中设置标志并轮询标志来阻止事件被调用的方法:

private object DoAsynchronousCallSynchronously()
{
    int completed = 0;
    AsynchronousObject obj = new AsynchronousObject();
    obj.OnCompletedCallback += delegate { Interlocked.Increment(ref completed); };
    obj.StartWork();

    // Busy loop
    while (completed == 0)
        Thread.Sleep(50);

    // StartWork() has completed at this point.
    return obj.Result;
}

有没有办法在没有民意调查的情况下做到这一点？

Answer 1

    private object DoAsynchronousCallSynchronously()
    {
        AutoResetEvent are = new AutoResetEvent(false);
        AsynchronousObject obj = new AsynchronousObject();    
        obj.OnCompletedCallback += delegate 
        {
            are.Set();
        };    
        obj.StartWork();    

        are.WaitOne();
        // StartWork() has completed at this point.    
        return obj.Result;
    }