wpf - DoEvents : Dispatcher. 调用与 PushFrame

Question

最近我发现了一种方法，它可以执行调度程序队列中的所有待处理消息，直到指定优先级。我之前已经有这样的代码，但它们使用完全不同的方法。这是他们两个:

PushFrame方式:

/// <summary>
/// Enters the message loop to process all pending messages down to the specified
/// priority. This method returns after all messages have been processed.
/// </summary>
/// <param name="priority">Minimum priority of the messages to process.</param>
public static void DoEvents(
    DispatcherPriority priority = DispatcherPriority.Background)
{
    DispatcherFrame frame = new DispatcherFrame();
    Dispatcher.CurrentDispatcher.BeginInvoke(
        priority,
        new DispatcherOperationCallback(ExitFrame), frame);
    Dispatcher.PushFrame(frame);
}

private static object ExitFrame(object f)
{
    ((DispatcherFrame) f).Continue = false;
    return null;
}

来源: MSDN Library

阻塞调用方式:

private static Action EmptyDelegate = delegate { };

/// <summary>
/// Processes all pending messages down to the specified priority.
/// This method returns after all messages have been processed.
/// </summary>
/// <param name="priority">Minimum priority of the messages to process.</param>
public static void DoEvents2(
    DispatcherPriority priority = DispatcherPriority.Background)
{
    Dispatcher.CurrentDispatcher.Invoke(EmptyDelegate, priority);
}

来源: Blog

哪个更好，两种解决方案之间是否存在任何功能差异？

更新:这是内联代表的第二个，与第一个一样，使其更短:

/// <summary>
/// Processes all pending messages down to the specified priority.
/// This method returns after all messages have been processed.
/// </summary>
/// <param name="priority">Minimum priority of the messages to process.</param>
public static void DoEvents2(
    DispatcherPriority priority = DispatcherPriority.Background)
{
    Dispatcher.CurrentDispatcher.Invoke(new Action(delegate { }), priority);
}

Answer 1

你有点回答了你自己的问题。您选择哪个并不重要，因为两者在后台执行相同的操作。

两者都遇到了这个:

While (dispatcherFrame.Continue)
{
  Dispatcher.GetMessage();
  Dispatcher.TranslateAndDispatch();
}

但是 PushFrame 更好一些，因为您不需要创建空委托(delegate)。