c++ - 如何防止 Win32 应用程序在主窗口关闭后在后台运行？

Question

我是 Win32 API 的初学者，但我对 C++ 有中等经验。出于学习目的，我根据引用资料、教程和示例创建了一个非常简单的 Win32 应用程序。

问题是，主窗口关闭后，它的进程还在后台运行。我怎样才能防止这种情况发生？在我的 WndProc 函数中，我确实有一个带有 DestroyWindow 的 WM_DESTROY 案例，但它似乎并没有起到作用。代码如下:

#include <cstdio>
#include <cstdlib>

#ifdef UNICODE
#include <tchar.h>
#endif

#include <Windows.h>

HINSTANCE hinst;
HWND hwnd;

LRESULT CALLBACK WndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

#ifdef UNICODE
int WINAPI _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow)
#else
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
#endif
{
    MSG msg;
    WNDCLASSEX mainclass;
    BOOL bRet;
    UNREFERENCED_PARAMETER(lpCmdLine);

    mainclass.cbSize =          sizeof(WNDCLASSEX);
    mainclass.style =           CS_VREDRAW | CS_HREDRAW;
    mainclass.lpfnWndProc =     (WNDPROC) WndProc;
    mainclass.cbClsExtra =      NULL;
    mainclass.cbWndExtra =      NULL;
    mainclass.hInstance =       hInstance;
    mainclass.hIcon =           NULL;
    mainclass.hCursor =         LoadCursor(NULL, IDC_ARROW);
    mainclass.hbrBackground =   (HBRUSH) COLOR_WINDOW;
    mainclass.lpszMenuName =    NULL;
    mainclass.lpszClassName =   TEXT("MainWindowClass");
    mainclass.hIconSm =         NULL;

    if (!RegisterClassEx(&mainclass))
        return FALSE;

    hinst = hInstance;

    hwnd = CreateWindowEx(
        WS_EX_WINDOWEDGE,
        TEXT("MainWindowClass"),
        TEXT("Test Window"),
        WS_CAPTION | WS_VISIBLE | WS_SIZEBOX | WS_SYSMENU | WS_MINIMIZEBOX | WS_MAXIMIZEBOX,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        NULL,
        NULL,
        hinst,
        NULL);

    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);

    while ((bRet = GetMessage(&msg, NULL, 0, 0)) != 0)
    {
        if (bRet != -1)
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }
    return (int) msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    PAINTSTRUCT ps;
    switch(uMsg)
    {
    case WM_DESTROY:
        DestroyWindow(hwnd);
        break;
    case WM_PAINT:
        BeginPaint(hwnd, &ps);
        EndPaint(hwnd, &ps);
        break;
    default:
        return DefWindowProc(hwnd, uMsg, wParam, lParam);
    }
    return 0;
}

Answer 1

不要调用 DestroyWindow()。该消息告诉您您的窗口已被销毁。调用 PostQuitMessage(0) 退出应用程序。