Detailed introduction of C# registered control handler (SetConsoleCtrlHandler) function example-C#.Net Tutorial-php.cn

Detailed introduction of C# registered control handler (SetConsoleCtrlHandler) function example

黄舟

Release： 2017-03-13 17:50:44

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Add or remove application-defined HandlerRoutine functions from the calling process's handler function list.

Win32 API
Function:
Add or remove application-defined HandlerRoutine functions from the calling process's handler function list.
Function prototype:

BOOL SetConsoleCtrlHandler（
PHANDLER_ROUTINE HandlerRoutine, // 回调函数
BOOL Add // 表示添加还是删除
）；

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Return value: BOOL type
Parameters
Parameter HandlerRoutine: An application-defined pointer HandlerRoutine function to be added or deleted. This parameter can be NULL.
Parameter Add: If this parameter is TRUE, the handler is added, if it is false, the handler will be removed.
Return value:
If the function fails, the return value is 0. Otherwise, a non-0 value is returned. If you want to get more error information, call the GetLastError function.
To put it bluntly, it is a system call.
The first parameter is function pointer, which is the function above. The second parameter is a flag, if TRUE then install the hook, if FALSE then delete the hook.

Use the Windows API to intercept the message of the manual closing event of the Console to achieve this. Below I give a complete example:

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;

/************************************************************************/
/* CSharp控制台关闭事件改写
 * Powered by:testcs_dn
 * Blog://m.sbmmt.com/
 */
/************************************************************************/
namespace CSharp控制台关闭事件改写
{
    /// 
    /// 控制台关闭事件改写
    /// 这里展示了Windows API SetConsoleCtrlHandler函数的应用，同时展示了线程计时器的使用；
    /// Author:testcs_dn
    /// Date:2015-01-03
    /// 
    class Program
    {
        /// 
        /// 计时器回调函数，在这里处理计时时间是否到达的判断以及要做的事情；
        /// 
        /// 
        public static void workOvertimeTimerCallback(object obj)
        {
            DateTime dt = DateTime.Now;
            if (dt.Hour == 16 && dt.Minute > 0)
            {
                Console.WriteLine("ok");
            }
        }

        //计时器变量
        public static System.Threading.Timer workOvertimeTimer = null;

        //定义处理程序委托
        delegate bool ConsoleCtrlDelegate(int dwCtrlType);

        const int CTRL_CLOSE_EVENT = 2;

        //导入SetCtrlHandlerHandler API
        [DllImport("kernel32.dll")]
        private static extern bool SetConsoleCtrlHandler(ConsoleCtrlDelegate HandlerRoutine, bool Add);
        static void Main(string[] args)
        {
            ConsoleCtrlDelegate newDelegate = new ConsoleCtrlDelegate(HandlerRoutine);
            if (SetConsoleCtrlHandler(newDelegate, true))
            {
                //初始化计时器
                workOvertimeTimer = new System.Threading.Timer(new TimerCallback(workOvertimeTimerCallback), null, 1000, 10000);
                //这里执行你自己的任务，我举例输出“...”，为了展示长时间的任务，我用了一个死循环；
                //避免输出太多，使用了Sleep；
                //注意：Sleep的时间不可太长，否则可能影响Console.ReadKey()，导致不能接收用户输入；
                while (true)
                {
                    Console.WriteLine("...");
                    Thread.Sleep(100);
                }
            }
            else
            {
                Console.WriteLine("抱歉，API注入失败，按任意键退出！");
                Console.ReadKey();
            }
        }

        /// 
        /// 处理程序例程，在这里编写对指定事件的处理程序代码
        /// 
        /// 
        /// 
        static bool HandlerRoutine(int CtrlType)
        {
            switch (CtrlType)
            {
                case CTRL_CLOSE_EVENT:       //用户要关闭Console了
                    Console.WriteLine();
                    Console.WriteLine("任务还没有完成，确认要退出吗？（Y/N）");
                    ConsoleKeyInfo ki = Console.ReadKey();
                    return ki.Key == ConsoleKey.Y;
                default:
                    return true;
            }
        }
    }
}

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