How To Catch CTRL-C, Break In C# Console Application



TODO:

Have you ever wanted to detect or catch the user pressing CTRL+C, CTRL-BREAK, Window Close, or Logoff / Shutdown Event in your console application?

 

SOLUTION:

 

using System;
using System.Collections.Generic;
using System.IO;
using System.Xml;
using System.Text;
using System.Text.RegularExpressions;
using System.Runtime.InteropServices;
using System.Threading;
using System.Reflection;

namespace ConsoleApplication1
{

    class ControlChecker
    {
        #region GLOBAL VARS
        private static readonly Mutex mutex = new Mutex(true, Assembly.GetExecutingAssembly().GetName().CodeBase);
        private static bool _userRequestExit = false;
        private static bool _doIStop = false;
        static HandlerRoutine consoleHandler;
        #endregion

        [DllImport("Kernel32")]
        public static extern bool SetConsoleCtrlHandler(HandlerRoutine Handler, bool Add);

        // A delegate type to be used as the handler routine for SetConsoleCtrlHandler.
        public delegate bool HandlerRoutine(CtrlTypes CtrlType);

        // An enumerated type for the control messages sent to the handler routine.
        public enum CtrlTypes
        {
            CTRL_C_EVENT = 0,
            CTRL_BREAK_EVENT,
            CTRL_CLOSE_EVENT,
            CTRL_LOGOFF_EVENT = 5,
            CTRL_SHUTDOWN_EVENT
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="ctrlType"></param>
        /// <returns></returns>
        private static bool ConsoleCtrlCheck(CtrlTypes ctrlType)
        {
            // Put your own handler here
            switch (ctrlType)
            {
                case CtrlTypes.CTRL_C_EVENT:
                    _userRequestExit = true;
                    Console.WriteLine("CTRL+C received, shutting down");
                    break;

                case CtrlTypes.CTRL_BREAK_EVENT:
                    _userRequestExit = true;
                    Console.WriteLine("CTRL+BREAK received, shutting down");
                    break;

                case CtrlTypes.CTRL_CLOSE_EVENT:
                    _userRequestExit = true;
                    Console.WriteLine("Program being closed, shutting down");
                    break;

                case CtrlTypes.CTRL_LOGOFF_EVENT:
                case CtrlTypes.CTRL_SHUTDOWN_EVENT:
                    _userRequestExit = true;
                    Console.WriteLine("User is logging off!, shutting down");
                    break;
            }

            return true;
        }

        /// <summary>
        /// Main entry point
        /// </summary>
        /// <param name="args"></param>
        /// <returns></returns>        
        static int Main(string[] args)
        {
            try
            {
                //make sure we only have one....
                if (!mutex.WaitOne(TimeSpan.Zero, true))
                {
                    Console.WriteLine("Another instance already running");
                    Thread.Sleep(5000);
                    return 1;
                }

                //save a reference so it does not get GC'd
                consoleHandler = new HandlerRoutine(ConsoleCtrlCheck);

                //set our handler here that will trap exit
                SetConsoleCtrlHandler(consoleHandler, true);

                DoMyTask();

                return 0;
            }
            catch (Exception x)
            {
                Console.WriteLine("Main Error [{0}]", x.Message);
                return -1;
            }
        }

       

        /// <summary>
        /// Run the export
        /// </summary>
        /// <param name="pAuthority"></param>
        /// <returns></returns>
        private static void DoMyTask()
        {
            //execcute until we have no more records to process
            while (!_doIStop)
            {
                //did user request exit?
                if (_userRequestExit)
                {
                    _doIStop = true;    //set flag to exit loop.  Other conditions could cause this too, which is why we use a seperate variable
                    Console.WriteLine("Shutting down, user requested exit");
                    break;
                }

                //do some other stuff here
                Console.WriteLine(String.Format("{0}, no exit requested yet...", DateTime.Now));
                //sleep 1 second
                Thread.Sleep(1000);    
            }
        }
    }
}

 


NOTES:

Open up Visual Studio.  Create a new Console Application Project.  Copy the entire code above, and replace ALL of the code in your program.cs main file.  Hit CTRL-F5, then test the break conditions above.



Comments (1) -

J. Thomas
J. Thomas
9/27/2011 10:16:22 AM #

Worked perfectly!

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