c# - 线程 sleep 在 Windows Phone 7 上运行不佳

Question

我想让我的程序休眠几秒钟。当我使用 thread.sleep(x) 时，整个程序没有响应。根据这篇文章 -> http://msdn.microsoft.com/en-us/library/hh184840(v=VS.92).aspx不负责3秒的应用不通过认证:/(我要等5秒)。

Answer 1

不要让应用程序的主线程休眠。相反，做任何需要在应用程序的后台线程中等待的事情。

如果您在应用程序的主线程中调用 Thread.Sleep()，应用程序将无法响应幕后的 UI 消息循环，如您所见。这是因为您在处理一条消息(触发等待的 UI 事件)时阻止了执行，因此无法处理该应用的其他消息。

相反，构建此代码以异步运行。我猜想有一些方法包含大部分繁重的工作，包括 sleep 。只要它不是事件处理程序(如果是，就重构它)，你可以设置第二个线程来运行这个方法，并添加一个“回调”方法，该方法将在它完成时调用，这将更新 UI结果。这需要多做一些工作，但它可以保持应用程序的响应速度，而且这通常是一种很好的做法，尤其是在多核设备上(现在甚至手机都配备了双核 CPU)。有许多方法可以设置多线程操作。 Delegate.BeginInvoke 是我的最爱:

public delegate void BackgroundMethod()

public void HandleUITrigger(object sender, EventArgs e)
{
   //we'll assume the user does something to trigger this wait.

   //set up a BackgroundMethod delegate to do our time-intensive task
   BackgroundMethod method = DoHeavyLifting;

   //The Delegate.BeginInvoke method schedules the delegate to run on 
   //a thread from the CLR's ThreadPool, and handles the callback.
   method.BeginInvoke(HeavyLiftingFinished, null);

   //The previous method doesn't block the thread; the main thread will move on
   //to the next message from the OS, keeping the app responsive.
}

public void DoHeavyLifting()
{
   //Do something incredibly time-intensive
   Thread.Sleep(5000);

   //Notice we don't have to know that we're being run in another thread,
   //EXCEPT this method cannot update the UI directly; to update the UI
   //we must call Control.Invoke() or call a method that Invokes itself
   ThreadSafeUIUpdate();
}

public void ThreadSafeUIUpdate()
{
   //A simple, thread-safe way to make sure that "cross-threading" the UI
   //does not occur. The method re-invokes itself on the main thread if necessary
   if(InvokeRequired)
   {
      this.Invoke((MethodInvoker)ThreadSafeUIUpdate);
      return;
   }

   //Do all your UI updating here.
}

public void HeavyLiftingFinished()
{
   //This method is called on the main thread when the thread that ran 
   //DoHeavyLifting is finished. You can call EndInvoke here to get
   //any return values, and/or clean up afterward.
}