注册控件处理程序函数

  • 项目

基本控件处理程序示例

这是用于安装控件处理程序的 SetConsoleCtrlHandler 函数的示例。

收到 CTRL+C 信号时，控件处理程序返回 TRUE，指示它已处理信号。 这样可防止调用其他控件处理程序。

收到 CTRL_CLOSE_EVENT 信号时，控件处理程序返回 TRUE，进程终止。

收到 CTRL_BREAK_EVENT、CTRL_LOGOFF_EVENT 或 CTRL_SHUTDOWN_EVENT 信号时，控件处理程序返回 FALSE。 这样做会导致信号传递到下一个控件处理程序函数。 如果尚未注册其他控件处理程序，或者没有已注册的处理程序返回 TRUE，将使用默认处理程序，因此进程终止。

注意

调用 AttachConsole、AllocConsole 或 FreeConsole 会将客户端进程中的控件处理程序表重置为其初始状态。 当附加的控制台会话更改时，必须重新注册处理程序。

// CtrlHandler.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include <windows.h>
#include <stdio.h>

BOOL WINAPI CtrlHandler(DWORD fdwCtrlType)
{
    switch (fdwCtrlType)
    {
        // Handle the CTRL-C signal.
    case CTRL_C_EVENT:
        printf("Ctrl-C event\n\n");
        Beep(750, 300);
        return TRUE;

        // CTRL-CLOSE: confirm that the user wants to exit.
    case CTRL_CLOSE_EVENT:
        Beep(600, 200);
        printf("Ctrl-Close event\n\n");
        return TRUE;

        // Pass other signals to the next handler.
    case CTRL_BREAK_EVENT:
        Beep(900, 200);
        printf("Ctrl-Break event\n\n");
        return FALSE;

    case CTRL_LOGOFF_EVENT:
        Beep(1000, 200);
        printf("Ctrl-Logoff event\n\n");
        return FALSE;

    case CTRL_SHUTDOWN_EVENT:
        Beep(750, 500);
        printf("Ctrl-Shutdown event\n\n");
        return FALSE;

    default:
        return FALSE;
    }
}

int main(void)
{
    if (SetConsoleCtrlHandler(CtrlHandler, TRUE))
    {
        printf("\nThe Control Handler is installed.\n");
        printf("\n -- Now try pressing Ctrl+C or Ctrl+Break, or");
        printf("\n    try logging off or closing the console...\n");
        printf("\n(...waiting in a loop for events...)\n\n");

        while (1) {}
    }
    else
    {
        printf("\nERROR: Could not set control handler");
        return 1;
    }
    return 0;
}

隐藏窗口侦听示例

按照注释，如果加载 gdi32.dll 或 user32.dll 库，则不会针对 CTRL_LOGOFF_EVENT 和 CTRL_SHUTDOWN_EVENT 事件调用 SetConsoleCtrlHandler。 指定的解决方法是通过调用 dwExStyle 参数设置为 0 并侦听 WM_QUERYENDSESSION 和 WM_ENDSESSION 窗口消息的CreateWindowEx 方法创建隐藏窗口（如果没有窗口）。 如果窗口已存在，则将这两条消息添加到现有窗口过程。

有关设置窗口及其消息循环的详细信息，请参阅创建窗口。

// CtrlHandler.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include <Windows.h>
#include <stdio.h>

BOOL WINAPI CtrlHandler(DWORD fdwCtrlType)
{
    switch (fdwCtrlType)
    {
        // Handle the CTRL-C signal.
    case CTRL_C_EVENT:
        printf("Ctrl-C event\n\n");
        Beep(750, 300);
        return TRUE;

        // CTRL-CLOSE: confirm that the user wants to exit.
    case CTRL_CLOSE_EVENT:
        Beep(600, 200);
        printf("Ctrl-Close event\n\n");
        return TRUE;

        // Pass other signals to the next handler.
    case CTRL_BREAK_EVENT:
        Beep(900, 200);
        printf("Ctrl-Break event\n\n");
        return FALSE;

    case CTRL_LOGOFF_EVENT:
        Beep(1000, 200);
        printf("Ctrl-Logoff event\n\n");
        return FALSE;

    case CTRL_SHUTDOWN_EVENT:
        Beep(750, 500);
        printf("Ctrl-Shutdown event\n\n");
        return FALSE;

    default:
        return FALSE;
    }
}

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch (uMsg)
    {
    case WM_QUERYENDSESSION:
    {
        // Check `lParam` for which system shutdown function and handle events.
        // See https://learn.microsoft.com/windows/win32/shutdown/wm-queryendsession
        return TRUE; // Respect user's intent and allow shutdown.
    }
    case WM_ENDSESSION:
    {
        // Check `lParam` for which system shutdown function and handle events.
        // See https://learn.microsoft.com/windows/win32/shutdown/wm-endsession
        return 0; // We have handled this message.
    }
    default:
        return DefWindowProc(hwnd, uMsg, wParam, lParam);
    }
}

int main(void)
{
    WNDCLASS sampleClass{ 0 };
    sampleClass.lpszClassName = TEXT("CtrlHandlerSampleClass");
    sampleClass.lpfnWndProc = WindowProc;

    if (!RegisterClass(&sampleClass))
    {
        printf("\nERROR: Could not register window class");
        return 2;
    }

    HWND hwnd = CreateWindowEx(
        0,
        sampleClass.lpszClassName,
        TEXT("Console Control Handler Sample"),
        0,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        nullptr,
        nullptr,
        nullptr,
        nullptr
    );

    if (!hwnd)
    {
        printf("\nERROR: Could not create window");
        return 3;
    }

    ShowWindow(hwnd, SW_HIDE);

    if (SetConsoleCtrlHandler(CtrlHandler, TRUE))
    {
        printf("\nThe Control Handler is installed.\n");
        printf("\n -- Now try pressing Ctrl+C or Ctrl+Break, or");
        printf("\n    try logging off or closing the console...\n");
        printf("\n(...waiting in a loop for events...)\n\n");

        // Pump message loop for the window we created.
        MSG msg{};
        while (GetMessage(&msg, nullptr, 0, 0) > 0)
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
        return 0;
    }
    else
    {
        printf("\nERROR: Could not set control handler");
        return 1;
    }
}