我希望能够在C#控制台应用程序中捕获CTRL+ C,以便我可以在退出之前执行一些清理.这样做的最佳方式是什么？
该Console.CancelKeyPress事件被用于此目的.这就是它的用法:
public static void Main(string[] args)
{
Console.CancelKeyPress += delegate {
// call methods to clean up
};
while (true) {}
}
当用户按下Ctrl + C时,代理中的代码将运行并退出程序.这允许您通过调用必需方法来执行清理.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,正确的策略可能是在计算完成后告诉程序退出.以下代码给出了如何实现此示例的示例:
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,这意味着在委托之后继续执行.如果运行,程序将等待用户按Ctrl + C.当发生这种情况时,keepRunning变量会更改值,导致while循环退出.这是一种使程序优雅退出的方法.
请参阅MSDN:
Console.CancelKeyPress事件
包含代码示例的文章:
Ctrl-C和.NET控制台应用程序
我想补充乔纳斯的回答.在a上旋转bool将导致100%的CPU利用率,并且在等待CTRL+时浪费大量能量做很多事情C.
更好的解决方案是使用a 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();
}
这是一个完整的工作示例.粘贴到空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..");
}
}
}
这个问题非常类似于:
捕获控制台出口C#
这是我如何解决这个问题,并处理用户点击X以及Ctrl-C.请注意ManualResetEvents的使用.这将导致主线程进入休眠状态,从而释放CPU以在等待退出或清理时处理其他线程.注意:必须在main的末尾设置TerminationCompletedEvent.如果不这样做会导致终止时不必要的延迟,因为在终止应用程序时OS会超时.
namespace CancelSample
{
using System;
using System.Threading;
using System.Runtime.InteropServices;
internal class Program
{
///
/// Adds or removes an application-defined HandlerRoutine function from the list of handler functions for the calling process
///
/// A pointer to the application-defined HandlerRoutine function to be added or removed. This parameter can be NULL.
/// If this parameter is TRUE, the handler is added; if it is FALSE, the handler is removed.
/// If the function succeeds, the return value is true.
[DllImport("Kernel32")]
private static extern bool SetConsoleCtrlHandler(ConsoleCloseHandler handler, bool add);
///
/// The console close handler delegate.
///
///
/// The close reason.
///
///
/// True if cleanup is complete, false to run other registered close handlers.
///
private delegate bool ConsoleCloseHandler(int closeReason);
///
/// Event set when the process is terminated.
///
private static readonly ManualResetEvent TerminationRequestedEvent;
///
/// Event set when the process terminates.
///
private static readonly ManualResetEvent TerminationCompletedEvent;
///
/// Static constructor
///
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);
}
///
/// The main console entry point.
///
/// The commandline arguments.
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();
}
///
/// Method called when the user presses Ctrl-C
///
/// The close reason
private static bool OnConsoleCloseEvent(int reason)
{
// Signal termination
TerminationRequestedEvent.Set();
// Wait for cleanup
TerminationCompletedEvent.WaitOne();
// Don't run other handlers, just exit.
return true;
}
}
}
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