下面是一个完整的工作示例。粘贴到空的c#控制台项目:

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..");
        }
    }
}

我可以在离开前做一些清理工作。做这件事最好的方法是什么 这才是真正的目标:走出陷阱，做你自己的东西。以上两个答案都不是正确的。因为Ctrl+C只是退出应用程序的众多方法之一。

在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;
     }

...

我想补充一下乔纳斯的回答。在bool上旋转将导致100%的CPU利用率，并且在等待CTRL+C时浪费大量的能量。

更好的解决方案是使用ManualResetEvent来实际“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();
}

看到MSDN:

控制台。CancelKeyPress事件

带有代码示例的文章:

Ctrl-C和.NET控制台应用程序

控制台。CancelKeyPress事件用于此。下面是它的用法:

public static void Main(string[] args)
{
    Console.CancelKeyPress += delegate {
        // call methods to clean up
    };

    while (true) {}
}

当用户按Ctrl+C时，委托中的代码将运行，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，执行委托之后没有代码。

在其他情况下，这是行不通的。例如，如果程序当前正在执行不能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。下面的代码给出了如何实现的示例:

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");
    }
}

这段代码与第一个示例之间的区别在于，e.Cancel被设置为true，这意味着在委托之后继续执行。如果运行，程序等待用户按Ctrl+C。当这种情况发生时，keepprunning变量会改变值，从而导致while循环退出。这是一种使程序优雅退出的方法。

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);
}