Application.Current.Shutdown()与Application.Current.Dispatcher.BeginInvokeShutdown()

问题描述

首先要了解一些背景知识:我有一个WPF应用程序，它是旧版Win32应用程序的GUI前端.旧版应用程序在单独的线程中作为DLL运行.用户在UI中选择的命令将在该旧线程"上调用.

First a bit of background: I have a WPF application, which is a GUI-front-end to a legacy Win32-application. The legacy app runs as DLL in a separate thread. The commands the user chooses in the UI are invoked on that "legacy thread".

如果旧版线程"完成，则GUI前端将无法再执行任何有用的操作，因此我需要关闭WPF应用程序.因此，在线程方法的末尾，我调用Application.Current.Shutdown().

If the "legacy thread" finishes, the GUI-front-end cannot do anything useful anymore, so I need to shutdown the WPF-application. Therefore, at the end of the thread's method, I call Application.Current.Shutdown().

由于我不在主线程上，因此需要调用此命令.但是，然后我注意到Dispatcher也有BeginInvokeShutdown()来关闭调度程序.所以我的问题是:调用之间有什么区别

Since I am not on the main thread, I need to invoke this command. However, then I noticed that the Dispatcher also has BeginInvokeShutdown() to shutdown the dispatcher. So my question is: What is the difference between invoking

Application.Current.Shutdown();

并致电

Application.Current.Dispatcher.BeginInvokeShutdown();

推荐答案

我进行了更多测试，现在我想我知道其中的区别:

I did some more testing, and now I think I know the differences:

1)如MSDN页面中所述，BeginInvokeShutdown除了关闭Dispatcher之外，还清除/中止其队列. Shutdown首先处理Dispatcher队列中的所有项目.

1) As stated in the MSDN page, BeginInvokeShutdown, besides shutting down the Dispatcher, also clears/aborts its queue. Shutdown first handles all items in the Dispatcher queue.

2)在应用程序中，我可以处理应用程序.Exit 事件.当我调用Shutdown时会触发此事件，但在我调用BeginInvokeShutdown时不会触发该事件！ Window.Closing 和 Window.Closed .

2) In an application I can handle the Application.Exit event. This event is fired when I call Shutdown, but NOT fired when I call BeginInvokeShutdown! The same applies to Window.Closing and Window.Closed.

关于相似性，在两种情况下都退出了主线程.根据其他正在运行的线程，这也会关闭进程:非后台线程在进程退出之前运行完毕.

As for similarities, in both cases the main thread is exited. Depending on other running threads, this also shuts down the process: non-background threads are run to completion before the process exits.

下面是我的测试代码.注释Application_Startup中的一个或另一个方法调用:

Below is my test code. Comment one or the other method call in Application_Startup:

public partial class App
{
    private void Application_Exit(object sender, ExitEventArgs e)
    {
        MessageBox.Show("Exiting");
    }

    private void Application_Startup(object sender, StartupEventArgs e)
    {
        var testThread = new Thread(
            () =>
            {
                Thread.Sleep(2000);
                Application.Current.Dispatcher.BeginInvokeShutdown(System.Windows.Threading.DispatcherPriority.Send);
                //Application.Current.Dispatcher.BeginInvoke(new Action(() => Application.Current.Shutdown()));
            });
        testThread.Start();
    }
}

public partial class Window1
{
    public Window1()
    {
        this.InitializeComponent();

        Dispatcher.BeginInvoke(new Action(() =>
        {
            Thread.Sleep(1000);
            Console.WriteLine("One");
        }));

        Dispatcher.BeginInvoke(new Action(() =>
        {
            Thread.Sleep(1000);
            Console.WriteLine("Two");
        }));

        Dispatcher.BeginInvoke(new Action(() =>
        {
            Thread.Sleep(1000);
            Console.WriteLine("Three");
        }));

        Dispatcher.BeginInvoke(new Action(() =>
        {
            Thread.Sleep(1000);
            Console.WriteLine("Four");
        }));
    }

    private void Window_Closed(object sender, EventArgs e)
    {
        Console.WriteLine("Closed");
    }

    private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
    {
        Console.WriteLine("Closing");
    }
}

这篇关于Application.Current.Shutdown()与Application.Current.Dispatcher.BeginInvokeShutdown()的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！