C＃：如何异步捕获事件并同步从函数返回值

Question

这是一个C＃问题 我想对异步事件回调进行同步调用。 请参阅代码中的注释

class User
{
    EventHandler Service1Started()
    {
      "Looks like service 1 started as I got event from server class" ;
    }
    EventHandler Service2Started()
    {
      "Looks like service 2 started as I got event from server class" ;
    }
    public void StartServicesOnlyStartService2AfterService1Started()
    {
        Server server = new Server();

         // want to call these 2 methods synchronously here
        // how to wait till service1 has started thru the event we get
        // Want to avoid polling, sleeping etc if possible

        server.StartService1();              
        server.StartService2();

    }
}

Answer 1

您的代码非常不清楚，但最简单的方法就是为Service1启动服务2的事件处理程序：

server.Service1Started += delegate { server.StartService2(); };

Answer 2

Jon的答案是对的，如果使用delegate不方便，这是等效的：

EventHandler Service1Started()
{
    // Looks like service 1 started as I got event from server class
    server.StartService2();
}