如何在 C# 控制台应用中捕获 Ctrl+C (SIGINT)
本文关键字:Ctrl+C SIGINT 控制台 应用 | 更新日期: 2023-09-27 17:47:21
我希望能够在 C# 控制台应用程序中捕获 Ctrl+C,以便在退出之前执行一些清理。最好的方法是什么?
Console.CancelKeyPress 事件用于此目的。它是这样使用的:
public static void Main(string[] args)
{
Console.CancelKeyPress += delegate {
// call methods to clean up
};
while (true) {}
}
当用户按 Ctrl+C 时,将运行委托中的代码,程序将退出。这允许您通过调用必要的方法来执行清理。请注意,执行委托后没有代码。
在其他情况下,这不会削减它。例如,如果程序当前正在执行无法立即停止的重要计算。在这种情况下,正确的策略可能是告诉程序在计算完成后退出。以下代码给出了如何实现这一点的示例:
class MainClass
{
private static bool keepRunning = true;
public static void Main(string[] args)
{
Console.CancelKeyPress += delegate(object? sender, ConsoleCancelEventArgs e) {
e.Cancel = true;
MainClass.keepRunning = false;
};
while (MainClass.keepRunning) {
// Do your work in here, in small chunks.
// If you literally just want to wait until Ctrl+C,
// not doing anything, see the answer using set-reset events.
}
Console.WriteLine("exited gracefully");
}
}
此代码与第一个示例之间的区别在于e.Cancel
设置为 true,这意味着在委托后继续执行。如果运行,程序将等待用户按 Ctrl+C。发生这种情况时,keepRunning
变量会更改值,从而导致 while 循环退出。这是一种使程序正常退出的方法。
请参阅 MSDN:
控制台.取消按键事件
包含代码示例的文章:
Ctrl-C 和 .NET 控制台应用程序
补充一下乔纳斯的答案。在bool
上旋转会导致 100% 的 CPU 利用率,并在等待 CTRL+C 时浪费大量精力做很多事情。
更好的解决方案是使用ManualResetEvent
实际"等待"CTRL + C:
static void Main(string[] args) {
var exitEvent = new ManualResetEvent(false);
Console.CancelKeyPress += (sender, eventArgs) => {
eventArgs.Cancel = true;
exitEvent.Set();
};
var server = new MyServer(); // example
server.Run();
exitEvent.WaitOne();
server.Stop();
}
这是一个完整的工作示例。 粘贴到空的 C# 控制台项目中:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
namespace TestTrapCtrlC {
public class Program {
static bool exitSystem = false;
#region Trap application termination
[DllImport("Kernel32")]
private static extern bool SetConsoleCtrlHandler(EventHandler handler, bool add);
private delegate bool EventHandler(CtrlType sig);
static EventHandler _handler;
enum CtrlType {
CTRL_C_EVENT = 0,
CTRL_BREAK_EVENT = 1,
CTRL_CLOSE_EVENT = 2,
CTRL_LOGOFF_EVENT = 5,
CTRL_SHUTDOWN_EVENT = 6
}
private static bool Handler(CtrlType sig) {
Console.WriteLine("Exiting system due to external CTRL-C, or process kill, or shutdown");
//do your cleanup here
Thread.Sleep(5000); //simulate some cleanup delay
Console.WriteLine("Cleanup complete");
//allow main to run off
exitSystem = true;
//shutdown right away so there are no lingering threads
Environment.Exit(-1);
return true;
}
#endregion
static void Main(string[] args) {
// Some biolerplate to react to close window event, CTRL-C, kill, etc
_handler += new EventHandler(Handler);
SetConsoleCtrlHandler(_handler, true);
//start your multi threaded program here
Program p = new Program();
p.Start();
//hold the console so it doesn’t run off the end
while (!exitSystem) {
Thread.Sleep(500);
}
}
public void Start() {
// start a thread and start doing some processing
Console.WriteLine("Thread started, processing..");
}
}
}
这个问题与
:捕获控制台出口 C#
以下是我如何解决这个问题,并处理用户点击X和Ctrl-C.请注意ManualResetEvents的使用。这些将导致主线程休眠,从而释放 CPU 在等待退出或清理时处理其他线程。注意:有必要在主节点的末尾设置终止已完成事件。如果不这样做,则会导致不必要的终止延迟,因为操作系统在终止应用程序时超时。
namespace CancelSample
{
using System;
using System.Threading;
using System.Runtime.InteropServices;
internal class Program
{
/// <summary>
/// Adds or removes an application-defined HandlerRoutine function from the list of handler functions for the calling process
/// </summary>
/// <param name="handler">A pointer to the application-defined HandlerRoutine function to be added or removed. This parameter can be NULL.</param>
/// <param name="add">If this parameter is TRUE, the handler is added; if it is FALSE, the handler is removed.</param>
/// <returns>If the function succeeds, the return value is true.</returns>
[DllImport("Kernel32")]
private static extern bool SetConsoleCtrlHandler(ConsoleCloseHandler handler, bool add);
/// <summary>
/// The console close handler delegate.
/// </summary>
/// <param name="closeReason">
/// The close reason.
/// </param>
/// <returns>
/// True if cleanup is complete, false to run other registered close handlers.
/// </returns>
private delegate bool ConsoleCloseHandler(int closeReason);
/// <summary>
/// Event set when the process is terminated.
/// </summary>
private static readonly ManualResetEvent TerminationRequestedEvent;
/// <summary>
/// Event set when the process terminates.
/// </summary>
private static readonly ManualResetEvent TerminationCompletedEvent;
/// <summary>
/// Static constructor
/// </summary>
static Program()
{
// Do this initialization here to avoid polluting Main() with it
// also this is a great place to initialize multiple static
// variables.
TerminationRequestedEvent = new ManualResetEvent(false);
TerminationCompletedEvent = new ManualResetEvent(false);
SetConsoleCtrlHandler(OnConsoleCloseEvent, true);
}
/// <summary>
/// The main console entry point.
/// </summary>
/// <param name="args">The commandline arguments.</param>
private static void Main(string[] args)
{
// Wait for the termination event
while (!TerminationRequestedEvent.WaitOne(0))
{
// Something to do while waiting
Console.WriteLine("Work");
}
// Sleep until termination
TerminationRequestedEvent.WaitOne();
// Print a message which represents the operation
Console.WriteLine("Cleanup");
// Set this to terminate immediately (if not set, the OS will
// eventually kill the process)
TerminationCompletedEvent.Set();
}
/// <summary>
/// Method called when the user presses Ctrl-C
/// </summary>
/// <param name="reason">The close reason</param>
private static bool OnConsoleCloseEvent(int reason)
{
// Signal termination
TerminationRequestedEvent.Set();
// Wait for cleanup
TerminationCompletedEvent.WaitOne();
// Don't run other handlers, just exit.
return true;
}
}
}
检测 SIGTERM 和 Ctrl+C:
CancellationTokenSource ctSource = new();
CancellationToken ct = ctSource.Token;
void ExitHandler()
{
// You can add any arbitrary global clean up
Console.WriteLine("Exiting...");
ctSource.Cancel();
}
// Assign exit handler to be called when the process is terminated
// or the user hits CTRL+C
AppDomain.CurrentDomain.ProcessExit += (sender, args) => ExitHandler();
Console.CancelKeyPress += (sender, args) => ExitHandler();
// Then you can use the cancellation token to check for exit:
Console.WriteLine("Ready to gracefully shut down!");
while (!ct.IsCancellationRequested)
{
Console.WriteLine($"Exit not detected, waiting another 10s.");
Task.Delay(10000, ct).Wait(ct);
}
我可以在退出之前进行一些清理。最好的方法是什么 这才是真正的目标:陷阱出口,自己做东西。而上面的回答是不对的。因为,Ctrl + C只是退出应用程序的众多方法之一。
dotnet c# 中需要什么 - 所谓的取消令牌传递给Host.RunAsync(ct)
然后,在退出信号陷阱中,对于 Windows,它将是
private static readonly CancellationTokenSource cts = new CancellationTokenSource();
public static int Main(string[] args)
{
// For gracefull shutdown, trap unload event
AppDomain.CurrentDomain.ProcessExit += (sender, e) =>
{
cts.Cancel();
exitEvent.Wait();
};
Console.CancelKeyPress += (sender, e) =>
{
cts.Cancel();
exitEvent.Wait();
};
host.RunAsync(cts);
Console.WriteLine("Shutting down");
exitEvent.Set();
return 0;
}
。
Console.TreatControlCAsInput = true;
对我有用。